Making a clone as I cannot reopen the bug. My findings: Downstream added: export MOZ_USE_XINPUT2=1 to the start script. If I comment it out, it works again. So it this a GTK, plasma or Firefox issue? +++ This bug was initially created as a clone of Bug #1359226 +++ User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:53.0) Gecko/20100101 Firefox/53.0 Build ID: 20170414000000 Steps to reproduce: After a while, but not following any patterns, Firefox does not respond to mouse wheel scrolling. This started with Version 53. Prior to that there were no problems. If I Alt-Tab to another window and back to Ffx again, scrolling works - at least for a while. There are no steps to reproduce it - it happens intermittently. You scroll your mouse wheel, and nothing happens. OS: openSUSE 42.2 KDE, Firefox 53.0-2.1 (x86_64 form the Mozilla repo, but I have seen it on Windows 7 64bit once or twice as well. Additionally, but I do not know if this problem is related, the latest Versions of both Firefox (V 53) and Thunderbird (Version 52.0.1-2.1 x84_64, from the OBS Mozilla repo) have stopped responding to mouse wheel scrolling if they are not the active window. All versions prior to that responded to mouse wheel scrolled if the mouse pointer hovered over the Ffx or TB window regardless of whether Ffx/TB was the active window - as is common on Linux. I do not know if that is related: Actual results: 1) Intermittently, you scroll your mouse wheel, and nothing happens, even if Ffx is the active window. 2) Ffx no longer responds to mouse scrolls if it is not the active window, even if the mouse cursor hovers above the Ffx (or TB) content pane. Expected results: 1) You expect the mouse wheel to scroll the page. 2) In Linux, you expect the mouse wheel to scroll content even in a window that is not active if the mouse cursor hovers over the content.
Summary: Mousewheel action over Firefox doesn't work if Firefox window is not active → Mousewheel action over Firefox doesn't work if Firefox window is not active due to MOZ_USE_XINPUT2=1
(In reply to jiri slaby from comment #0) > Making a clone as I cannot reopen the bug. > > My findings: > Downstream added: > export MOZ_USE_XINPUT2=1 > to the start script. If I comment it out, it works again. So it this a GTK, > plasma or Firefox issue? (copying over my comment from bug 1359226, let's keep the discussion on this bug): We explicitly keep MOZ_USE_XINPUT2 off by default because behaviour is buggy when it is turned on. The code is at http://searchfox.org/mozilla-central/rev/13148faaa91a1c823a7d68563d9995480e714979/toolkit/xre/nsAppRunner.cpp#3850 and references a couple of bugs. From the discussion in those bugs it's still not clear to me whether this needs to be fixed in Firefox or elsewhere. Some of the comments seem to imply it affects other apps as well, not just Firefox, which would make it a GTK issue most likely. But I'm not sure.
Priority: -- → P5
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