7 ms·

Quite a curious bug that many people seem to have come across, some mention that they encounter it at least once a day, and yet I don't think I've seen this beh

Quite a curious bug that many people seem to have come across, some mention that they encounter it at least once a day, and yet I don't think I've seen this behaviour even once in the last decade and a half. It doesn't seem limited by OS either, so I wonder what the actual conditions for the bug to manifest itself were. (The only place I come across a similar bug is with LibreWolf (a customized privacy-enhanced Firefox). And I'm pretty sure that has to do with the fact that it's a flatpak, rather than to do with the browser itself, since no other Firefoxes I run have ever exhibited this behaviour.)

Izkata 3y ago
That would make sense to me - the only place I've seen this is with a snap app, I haven't seen it with firefox.
UnlockedSecrets 3y ago
I see this on a daily basis, Most times multiple times a day on a Linux KDE Plasma system with it installed natively on OpenSuse Tumbleweed. Best i could describe it is that it happens when i happen to switch to another virtual desktop using keyboard shortcuts on the exact same frame that the tool tip pops up. My guess is it was some kind of race condition that required very precise timing that made it difficult to narrow down, Paired with heavy use of keyboard shortcuts meaning alot of people likely were not effected by it. Very glad to hear it has been fixed and looking forward to getting a version of Firefox with it! I just did some testing and getting it to happen is as simple as hovering over it, And swapping to another virtual desktop before the popup shows up with firefox not being the new active application.
- prmoustache 3y ago
  I am in the same boat as the OP. I don't even know where I should click to see a tooltip to begin with!
  - bmicraft 3y ago
    Hover over "X hours ago" of your comment for example
    - prmoustache 3y ago
      Hmmm doesn't appear on my firefox, but I tested and the tooltip appear in ungoogled-chromium so I guess it is blocked by an extension I am using.
lifthrasiir 3y ago
I believe this is a common enough bug for many GUI systems. For example I have seen this behavior a lot from Windows 10 taskbars; the only way out was to hover the cursor on top of multi-window button and then out of the taskbar. A lot of websites also have a similar issue with a right condition. The main culprit seems to be a desynchronized event delivery, where you are expected to receive an event when the cursor exits but somehow weren't, for example because the window focus was lost so no further mouse events couldn't be delivered (depending on OS and preferences). Unless there is a dedicated way to reliably detect such cases (e.g. DOM `onmouseleave` or `onmouseout`), workaround and hacks would be needed---for example when the window focus was lost it can generate synthetic events.
- kelnos 3y ago
  Hm, is that assumption correct? I don't know about Windows, but on Linux/X11, app windows do get mouse-enter/move/leave events even if they are not focused.
  - lifthrasiir 3y ago
    This is highly specific to toolkits, but windows in Windows (wink) do not receive mouse events unless they are configured to "capture" mouse events (`SetCapture`). And even when there exist APIs for them, the existence of faulty websites suggests that the easiest path is probably incorrect anyway.
  - DonHopkins 3y ago
    The Devil is in the details. And in the case of the X11 Devil, they're literally named "detail", and they sound weird enough for Elon Musk to name his children after. https://tronche.com/gui/x/xlib/events/window-entry-exit/ https://tronche.com/gui/x/xlib/events/window-entry-exit/ typedef struct { int type; /* EnterNotify or LeaveNotify */ unsigned long serial; /* # of last request processed by server */ Bool send_event; /* true if this came from a SendEvent request */ Display *display; /* Display the event was read from */ Window window; /* ``event'' window reported relative to */ Window root; /* root window that the event occurred on */ Window subwindow; /* child window */ Time time; /* milliseconds */ int x, y; /* pointer x, y coordinates in event window */ int x_root, y_root; /* coordinates relative to root */ int mode; /* NotifyNormal, NotifyGrab, NotifyUngrab */ int detail; /* * NotifyAncestor, NotifyVirtual, NotifyInferior, * NotifyNonlinear,NotifyNonlinearVirtual */ Bool same_screen; /* same screen flag */ Bool focus; /* boolean focus */ unsigned int state; /* key or button mask */ } XCrossingEvent; typedef XCrossingEvent XEnterWindowEvent; typedef XCrossingEvent XLeaveWindowEvent; More details (these are just the "normal" ones, just wait till you read about "abnormal" NotifyGrab and NotifyUngrab mode and input focus events, and how grabbing interacts with input focus, and key map state notifications): https://tronche.com/gui/x/xlib/events/window-entry-exit/normal.html https://tronche.com/gui/x/xlib/events/window-entry-exit/norm... https://tronche.com/gui/x/xlib/events/window-entry-exit/grab-ungrab.html https://tronche.com/gui/x/xlib/events/window-entry-exit/grab... https://tronche.com/gui/x/xlib/events/input-focus/ https://tronche.com/gui/x/xlib/events/input-focus/ https://tronche.com/gui/x/xlib/events/input-focus/normal-and-grabbed.html https://tronche.com/gui/x/xlib/events/input-focus/normal-and... https://tronche.com/gui/x/xlib/events/input-focus/grab.html https://tronche.com/gui/x/xlib/events/input-focus/grab.html https://tronche.com/gui/x/xlib/events/key-map.html https://tronche.com/gui/x/xlib/events/key-map.html And then you have colormaps and visuals: https://donhopkins.medium.com/the-x-windows-disaster-128d398ebd47 https://donhopkins.medium.com/the-x-windows-disaster-128d398... >The color situation is a total flying circus. The X approach to device independence is to treat everything like a MicroVAX framebuffer on acid. A truly portable X application is required to act like the persistent customer in Monty Python’s “Cheese Shop” sketch, or a grail seeker in “Monty Python and the Holy Grail.” Even the simplest applications must answer many difficult questions: WHAT IS YOUR DISPLAY? display = XOpenDisplay("unix:0"); WHAT IS YOUR ROOT? root = RootWindow(display, DefaultScreen(display)); AND WHAT IS YOUR WINDOW? win = XCreateSimpleWindow(display, root, 0, 0, 256, 256, 1, BlackPixel( display, DefaultScreen(display)), WhitePixel( display, DefaultScreen(display))); OH ALL RIGHT, YOU CAN GO ON. (the next client tries to connect to the server) WHAT IS YOUR DISPLAY? display = XOpenDisplay("unix:0"); WHAT IS YOUR COLORMAP? cmap = DefaultColormap(display, DefaultScreen(display)); AND WHAT IS YOUR FAVORITE COLOR? favorite_color = 0; /* Black. */ /* Whoops! No, I mean: */ favorite_color = BlackPixel(display, DefaultScreen(display)); /* AAAYYYYEEEEE!! */ (client dumps core & falls into the chasm) WHAT IS YOUR DISPLAY? display = XOpenDisplay("unix:0"); WHAT IS YOUR VISUAL? struct XVisualInfo vinfo; if (XMatchVisualInfo(display, DefaultScreen(display), 8, PseudoColor, &vinfo) != 0) visual = vinfo.visual; AND WHAT IS THE NET SPEED VELOCITY OF AN XConfigureWindow REQUEST? /* Is that a SubstructureRedirectMask or a ResizeRedirectMask? */ WHAT??! HOW AM I SUPPOSED TO KNOW THAT? AAAAUUUGGGHHH!!!! (server dumps core & falls into the chasm)
Lammy 3y ago
I experienced the bug a lot when interacting with YouTube video embeds on other web pages. It goes like: hover cursor over the embedded player's full screen control, "Full screen (f)" tooltip appears, click control, video goes full screen but tooltip remains over top of playing video. (Lunix X11 with MATE's Marco wm)
crote 3y ago
It's a very workflow-specific bug. I pretty much only encounter it while playing video games. Turns out that while gaming I often have a Youtube video playing in one browser tab, and use another browser tab to look up game-related information. So it is really common for me to interact with the tab bar (which triggers the tooltip) right before alt-tabbing into my game. During day-to-day browser use my cursor is almost always located somewhere over the website content - which rarely triggers a tooltip.
looping8 3y ago
It's the same thing with games - whenever a game from a studio known for "broken" titles comes out, people post compilations of strange things happening, and it just never happens on my end. Natural bug resistance, perhaps. However, I do frequently get an innocent bug, where opening my bookmark toolbar's extension (the >> icon in the top right) results in it displaying all the bookmarks in a drop-down list, instead of the ones not appearing on the toolbar.

Izkata 3y ago

That would make sense to me - the only place I've seen this is with a snap app, I haven't seen it with firefox.

UnlockedSecrets 3y ago

I see this on a daily basis, Most times multiple times a day on a Linux KDE Plasma system with it installed natively on OpenSuse Tumbleweed. Best i could describe it is that it happens when i happen to switch to another virtual desktop using keyboard shortcuts on the exact same frame that the tool tip pops up. My guess is it was some kind of race condition that required very precise timing that made it difficult to narrow down, Paired with heavy use of keyboard shortcuts meaning alot of people likely were not effected by it. Very glad to hear it has been fixed and looking forward to getting a version of Firefox with it! I just did some testing and getting it to happen is as simple as hovering over it, And swapping to another virtual desktop before the popup shows up with firefox not being the new active application.

prmoustache 3y ago
I am in the same boat as the OP. I don't even know where I should click to see a tooltip to begin with!
- bmicraft 3y ago
  Hover over "X hours ago" of your comment for example
  - prmoustache 3y ago
    Hmmm doesn't appear on my firefox, but I tested and the tooltip appear in ungoogled-chromium so I guess it is blocked by an extension I am using.

lifthrasiir 3y ago

I believe this is a common enough bug for many GUI systems. For example I have seen this behavior a lot from Windows 10 taskbars; the only way out was to hover the cursor on top of multi-window button and then out of the taskbar. A lot of websites also have a similar issue with a right condition. The main culprit seems to be a desynchronized event delivery, where you are expected to receive an event when the cursor exits but somehow weren't, for example because the window focus was lost so no further mouse events couldn't be delivered (depending on OS and preferences). Unless there is a dedicated way to reliably detect such cases (e.g. DOM `onmouseleave` or `onmouseout`), workaround and hacks would be needed---for example when the window focus was lost it can generate synthetic events.

kelnos 3y ago
Hm, is that assumption correct? I don't know about Windows, but on Linux/X11, app windows do get mouse-enter/move/leave events even if they are not focused.
- lifthrasiir 3y ago
  This is highly specific to toolkits, but windows in Windows (wink) do not receive mouse events unless they are configured to "capture" mouse events (`SetCapture`). And even when there exist APIs for them, the existence of faulty websites suggests that the easiest path is probably incorrect anyway.
- DonHopkins 3y ago
  The Devil is in the details. And in the case of the X11 Devil, they're literally named "detail", and they sound weird enough for Elon Musk to name his children after. https://tronche.com/gui/x/xlib/events/window-entry-exit/ https://tronche.com/gui/x/xlib/events/window-entry-exit/ typedef struct { int type; /* EnterNotify or LeaveNotify */ unsigned long serial; /* # of last request processed by server */ Bool send_event; /* true if this came from a SendEvent request */ Display *display; /* Display the event was read from */ Window window; /* ``event'' window reported relative to */ Window root; /* root window that the event occurred on */ Window subwindow; /* child window */ Time time; /* milliseconds */ int x, y; /* pointer x, y coordinates in event window */ int x_root, y_root; /* coordinates relative to root */ int mode; /* NotifyNormal, NotifyGrab, NotifyUngrab */ int detail; /* * NotifyAncestor, NotifyVirtual, NotifyInferior, * NotifyNonlinear,NotifyNonlinearVirtual */ Bool same_screen; /* same screen flag */ Bool focus; /* boolean focus */ unsigned int state; /* key or button mask */ } XCrossingEvent; typedef XCrossingEvent XEnterWindowEvent; typedef XCrossingEvent XLeaveWindowEvent; More details (these are just the "normal" ones, just wait till you read about "abnormal" NotifyGrab and NotifyUngrab mode and input focus events, and how grabbing interacts with input focus, and key map state notifications): https://tronche.com/gui/x/xlib/events/window-entry-exit/normal.html https://tronche.com/gui/x/xlib/events/window-entry-exit/norm... https://tronche.com/gui/x/xlib/events/window-entry-exit/grab-ungrab.html https://tronche.com/gui/x/xlib/events/window-entry-exit/grab... https://tronche.com/gui/x/xlib/events/input-focus/ https://tronche.com/gui/x/xlib/events/input-focus/ https://tronche.com/gui/x/xlib/events/input-focus/normal-and-grabbed.html https://tronche.com/gui/x/xlib/events/input-focus/normal-and... https://tronche.com/gui/x/xlib/events/input-focus/grab.html https://tronche.com/gui/x/xlib/events/input-focus/grab.html https://tronche.com/gui/x/xlib/events/key-map.html https://tronche.com/gui/x/xlib/events/key-map.html And then you have colormaps and visuals: https://donhopkins.medium.com/the-x-windows-disaster-128d398ebd47 https://donhopkins.medium.com/the-x-windows-disaster-128d398... >The color situation is a total flying circus. The X approach to device independence is to treat everything like a MicroVAX framebuffer on acid. A truly portable X application is required to act like the persistent customer in Monty Python’s “Cheese Shop” sketch, or a grail seeker in “Monty Python and the Holy Grail.” Even the simplest applications must answer many difficult questions: WHAT IS YOUR DISPLAY? display = XOpenDisplay("unix:0"); WHAT IS YOUR ROOT? root = RootWindow(display, DefaultScreen(display)); AND WHAT IS YOUR WINDOW? win = XCreateSimpleWindow(display, root, 0, 0, 256, 256, 1, BlackPixel( display, DefaultScreen(display)), WhitePixel( display, DefaultScreen(display))); OH ALL RIGHT, YOU CAN GO ON. (the next client tries to connect to the server) WHAT IS YOUR DISPLAY? display = XOpenDisplay("unix:0"); WHAT IS YOUR COLORMAP? cmap = DefaultColormap(display, DefaultScreen(display)); AND WHAT IS YOUR FAVORITE COLOR? favorite_color = 0; /* Black. */ /* Whoops! No, I mean: */ favorite_color = BlackPixel(display, DefaultScreen(display)); /* AAAYYYYEEEEE!! */ (client dumps core & falls into the chasm) WHAT IS YOUR DISPLAY? display = XOpenDisplay("unix:0"); WHAT IS YOUR VISUAL? struct XVisualInfo vinfo; if (XMatchVisualInfo(display, DefaultScreen(display), 8, PseudoColor, &vinfo) != 0) visual = vinfo.visual; AND WHAT IS THE NET SPEED VELOCITY OF AN XConfigureWindow REQUEST? /* Is that a SubstructureRedirectMask or a ResizeRedirectMask? */ WHAT??! HOW AM I SUPPOSED TO KNOW THAT? AAAAUUUGGGHHH!!!! (server dumps core & falls into the chasm)

Lammy 3y ago

I experienced the bug a lot when interacting with YouTube video embeds on other web pages. It goes like: hover cursor over the embedded player's full screen control, "Full screen (f)" tooltip appears, click control, video goes full screen but tooltip remains over top of playing video. (Lunix X11 with MATE's Marco wm)

crote 3y ago

It's a very workflow-specific bug. I pretty much only encounter it while playing video games. Turns out that while gaming I often have a Youtube video playing in one browser tab, and use another browser tab to look up game-related information. So it is really common for me to interact with the tab bar (which triggers the tooltip) right before alt-tabbing into my game. During day-to-day browser use my cursor is almost always located somewhere over the website content - which rarely triggers a tooltip.

looping8 3y ago

It's the same thing with games - whenever a game from a studio known for "broken" titles comes out, people post compilations of strange things happening, and it just never happens on my end. Natural bug resistance, perhaps. However, I do frequently get an innocent bug, where opening my bookmark toolbar's extension (the >> icon in the top right) results in it displaying all the bookmarks in a drop-down list, instead of the ones not appearing on the toolbar.