This is a great example of why you should use platform UI, and shouldn't try to re-invent them: 1. Click the mouse and hold. The button doesn't depress (huh?)

This is a great example of why you should use platform UI, and shouldn't try to re-invent them: 1. Click the mouse and hold. The button doesn't depress (huh?) 2. Release the mouse button. Now it depresses (wtf). And actives. 3. Hover the mouse over it, it doesn't highlight. 4. Click the mouse and hold, then drag the mouse outside the button area. Release the mouse button. It depresses (ugh) and actives. 5. Click the disabled button while the progress dialog box is on screen. The progress box vanishes and the button actives 6. Attempt to active the button using the keyboard. 7. Attempt to make the button the focus for keyboard action by right-clicking or middle-clicking it (or click and drag out of it, but we already know that doesn't work). [This is a GTK feature] </rant>