> Just not on Windows with Firefox. I am pretty sure uMatrix works fine on Firefox/Windows: it's all HTML/CSS/JS code, and thus OS agnostic -- uMatrix does not

> Just not on Windows with Firefox. I am pretty sure uMatrix works fine on Firefox/Windows: it's all HTML/CSS/JS code, and thus OS agnostic -- uMatrix does not care about OS. Firefox is supposed to resize the popup panel according to the size of its content -- the resizing is Firefox's responsibility, it's out of reach of uMatrix. I believe there are issues in Firefox with regards to using multiple monitors with different DPI. In any case, you should report your issue to buzgilla.mozilla.org.