Making JFrame transparent breaks scrolling on Mac

Question

I have a transparent undecorated JFrame that I set using AWTUtilities.setWindowOpaque(this, false). On the JFrame, I have a scrollpane; it works perfectly on Windows. On the Mac, the whole JFrame is draggable; so when I try to scroll through the scrollpane by clicking and holding the mouse on the scrollbar, the entire frame moves instead of the scrollbar thumb. I also tried to use setBackground(new Color(0,0,0,0)) instead of setWindowOpaque(), but it has the same problem. Any ideas on how to fix this?

You might try setting the background to almost-transparent, e.g. Color(0,0,0,10) or so (not certain of the exact threshold). — technomage, Apr 04 '12 at 14:39
It seems like any kind of transparency breaks it. I tried Color(0,0,0,.99f) and it doesn't work. — user1309036, Apr 04 '12 at 14:47
@user1309036 : So sorry, can not test that, since I am using Windows :-( — nIcE cOw, Apr 04 '12 at 15:23
It's a usability feature for undecorated frames, which would otherwise be immoveable. See also this [example](http://stackoverflow.com/a/2166500/230513). — trashgod, Apr 04 '12 at 16:09
If you _don't_ click, does the mouse wheel scroll the content? — trashgod, Jun 17 '12 at 03:25

score 1 · Answer 1 · edited May 23 '17 at 12:20

As suggested in this similar thread, try:

getRootPane().putClientProperty("apple.awt.draggableWindowBackground", Boolean.FALSE);

If you choose to use this, the scrollbar will be usable and the window won't drag. However, you may be stuck with an immovable window, unless you add a MouseMotionListener and move the window around in the mouseDragged() method using a call like frame.setLocation().

Instead, you might be able to force the user to click on the scrollbar's arrow buttons, rather than drag the scrollbar itself... But that's not the most user-friendly idea I've ever seen.

Making JFrame transparent breaks scrolling on Mac

1 Answers1