Fix bitcoin-qt visual glitches on Wayland

diegoviola commented at 7:19 am on October 16, 2025: contributor

The main window (BitcoinGUI) does not need to be passed to bringToFront(), doing so sets Qt::WindowStaysOnTopHint on the main window and causes it to flicker.

Fixes #903.

DrahtBot commented at 7:19 am on October 16, 2025: contributor

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hebasto renamed this:
~~qt: fix Wayland visual glitches~~
Fix Wayland visual glitches
on Oct 16, 2025

in src/qt/guiutil.cpp:413 in 4daf53b12e outdated

406@@ -407,10 +407,6 @@ void bringToFront(QWidget* w)
407 {
408     if (w) {
409         if (QGuiApplication::platformName() == "wayland") {
410-            auto flags = w->windowFlags();
411-            w->setWindowFlags(flags|Qt::WindowStaysOnTopHint);
412-            w->show();
413-            w->setWindowFlags(flags);

hebasto commented at 11:09 am on October 16, 2025:

This code was introduced in #831.

cc @pablomartin4btc

diegoviola commented at 11:38 am on October 16, 2025:

@hebasto Thanks for letting me know. I managed to reproduce the artifacts/flicker with the original code on sway and labwc (wlroots-based compositors). In both cases, getting rid of the flags fixed the issue.

I’ve not tested this on KWin and Mutter yet, I plan on doing that later today. Hopefully we can come up with a solution that works everywhere.

in src/qt/guiutil.cpp:414 in 4daf53b12e

406@@ -407,10 +407,6 @@ void bringToFront(QWidget* w)
407 {
408     if (w) {
409         if (QGuiApplication::platformName() == "wayland") {
410-            auto flags = w->windowFlags();
411-            w->setWindowFlags(flags|Qt::WindowStaysOnTopHint);
412-            w->show();
413-            w->setWindowFlags(flags);
414             w->show();

hebasto commented at 12:37 pm on October 16, 2025:

Is it necessary now to call w->show(); here?

Would it be more clear to simply revert https://github.com/bitcoin-core/gui/commit/15aa7d023688700a47997b92108de95f2d864f5a?

diegoviola commented at 12:47 pm on October 16, 2025:

@hebasto Yeah, I think a revert would also do the trick.

diegoviola commented at 12:57 pm on October 16, 2025:

@hebasto compiling 30.0 with https://github.com/bitcoin-core/gui/commit/15aa7d023688700a47997b92108de95f2d864f5a reverted, will confirm soon.

diegoviola commented at 1:16 pm on October 16, 2025:

@hebasto Yeah, I can confirm that reverting https://github.com/bitcoin-core/gui/commit/15aa7d023688700a47997b92108de95f2d864f5a solves the problem for me (on sway).

diegoviola force-pushed on Oct 16, 2025

diegoviola requested review from hebasto on Oct 16, 2025

diegoviola force-pushed on Oct 16, 2025

pablomartin4btc commented at 4:25 pm on October 16, 2025: contributor

Concept ACK

If you can, please check how this behaves on #817.

diegoviola referenced this in commit 6542d5ff00 on Oct 18, 2025

diegoviola force-pushed on Oct 18, 2025

diegoviola referenced this in commit 949e953ebc on Oct 18, 2025

diegoviola force-pushed on Oct 18, 2025

diegoviola requested review from pablomartin4btc on Oct 18, 2025

diegoviola commented at 5:28 pm on October 18, 2025: contributor

@pablomartin4btc can you please re-review?

diegoviola force-pushed on Oct 18, 2025

qt: don't pass BitcoinGUI to bringToFront()

The main window (BitcoinGUI) does not need to be passed to
bringToFront(), doing so sets Qt::WindowStaysOnTopHint on the main
window and causes it to flicker.

Fixes #903.

095f920629

diegoviola force-pushed on Oct 18, 2025

diegoviola renamed this:
~~Fix Wayland visual glitches~~
Fix bitcoin-qt visual glitches on Wayland
on Oct 19, 2025

pablomartin4btc commented at 7:26 am on October 24, 2025: contributor

tested 095f920629207b5ec4c50de7b454dfced0eafefb and it fixes the problem.

I still need to check if this is the right approach, need to check against xcb and macOS. Also there are other places where bringToFront is being used, the rpcconsole has the same issue as the main window in wayland, so perhaps the fix has to be within bringToFront, need more time to test. Thanks for finding the issue and taking a look at this!

diegoviola commented at 4:31 pm on October 24, 2025: contributor

tested 095f920 and it fixes the problem.

Great! Thanks for confirming that.

I still need to check if this is the right approach, need to check against xcb and macOS.

Sure.

Also there are other places where bringToFront is being used, the rpcconsole has the same issue as the main window in wayland, so perhaps the fix has to be within bringToFront, need more time to test.

I am not able to reproduce the flickering with the rpcconsole specifically, but in a previous testing that I did removing these two lines helped with getting rid of some flickering, not all: https://github.com/bitcoin/bitcoin/blob/v30.0/src/qt/guiutil.cpp#L413-L414.

Can you please test if removing those help with the rpcconsole?

Thanks for finding the issue and taking a look at this!

You’re welcome, thank you for your work as well.

Fix bitcoin-qt visual glitches on Wayland #904

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