I have only tested and found this when moving objects around on a system panel and same when moving files/folders in the Dolphin file manager. The movement of the icon slows and falls behind mouse input. For example if I drag a file in Dolphin in the Dolphin window or the desktop rapidly it can take many seconds to finish completing the mouse input until it eventually lands where I let off the left-click to drop the object. Same thing happens when dragging an item on the system panel. Reproducible: Always Steps to Reproduce: 1. Click a file or system tray icon to move 2. Move the icon at any rate of speed 3. Remove finger from left-click button to end mouse input on the object being drug Actual Results: Icon moves in super slow motion and does not properly follow the mouse Expected Results: Have the icon being drug follow at the same speed and location of the mouse on screen OS: Kubuntu 15.10 with Neon Desktop repositories enabled and up to date CPU: Intel 4690K GPU: Nvidia GTX 970 with current proprietary drivers Nvidia GPU connected via DisplayPort to an Asus monitor running at 144Hz
that's because in Qt xcb it seems drag windows are marked as tooltips, that's wrong (tooltip animation KWin effect gets triggered for them) Martin: any idea how to heuristically detect such windows?
That's a bug in Qt event handling forgot how to compress events and/or Qt DnD is causing "something™" that is slow on at least the nvidia blob. The problem seem the repaints below (the faster the update, the more obvious the problem becomes, the compositor being a natural trigger but not the problem) https://bugs.kde.org/show_bug.cgi?id=352019#c28 You'll rather not get this problem with DnDs that are NOT Qt5, compositing or the tooltip animation should not matter. *** This bug has been marked as a duplicate of bug 352019 ***
I should also note that I was using OpenGL 3.1 for rendering with this
The compositor settings won't matter - it's most likely a known problem in Qt. Try to suspend the compositor (SHIFT+Alt+F12), run glxgears and move a drag over the running glxgears window. See what happens.
Git commit 3500c766f107d7ab2520c809cbf09f053a6f8062 by Martin Gräßlin. Committed on 14/04/2016 at 08:19. Pushed by graesslin into branch 'master'. add X11Integration for xcb qpa workarounds Summary: this class will collect some adjustments to the xcb qpa make the drag and drop window NOT to be a tooltip. This is a workaround for QtBug https://bugreports.qt.io/browse/QTBUG-52560 FIXED-IN: 5.7.0 Test Plan: Reviewers: graesslin, mart Subscribers: plasma-devel Projects: #plasma Differential Revision: https://phabricator.kde.org/D1402 M +2 -1 CMakeLists.txt M +2 -1 autotests/CMakeLists.txt M +29 -0 autotests/kdeplatformtheme_unittest.cpp M +3 -0 src/platformtheme/CMakeLists.txt M +5 -0 src/platformtheme/kdeplatformtheme.cpp M +2 -0 src/platformtheme/kdeplatformtheme.h A +53 -0 src/platformtheme/x11integration.cpp [License: LGPL (v2/3+eV)] A +40 -0 src/platformtheme/x11integration.h [License: LGPL (v2/3+eV)] http://commits.kde.org/plasma-integration/3500c766f107d7ab2520c809cbf09f053a6f8062
> 3. Remove finger from left-click button to end mouse input on the object being drug > Actual Results: > Icon moves in super slow motion and does not properly follow the mouse This is bug #352019 - altering the type won't help you since the morph ends within 250ms or so anyway. I don't say QTBUG-52560 isn't an *additional* "who cares about desktops" bug in Qt5, but I'd rather not expect this bug to be fixed by a workaround on the window type. @court, run "kcmshell5 kwineffects" and deactivate the "morphing tooltips" effect. Then check whether there's still a problem.
@Thomas, I did both of your suggestions and the dragging issue still persists both with system tray icons and folders/files in Dolphin anywhere on the screen and over the glxgears window
then the workaround from comment #5 has no impact beause it works around the wrong bug in qt. *** This bug has been marked as a duplicate of bug 352019 ***