Bug 467388 - Side- and top-tiled windows can inappropriately be resized from top window edge, which interferes with Fitts' Law for UI elements at that edge, such as browser tabs in CSD windows
Summary: Side- and top-tiled windows can inappropriately be resized from top window ed...
Status: CONFIRMED
Alias: None
Product: kwin
Classification: Plasma
Component: decorations (show other bugs)
Version: 5.27.3
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: usability
Depends on:
Blocks:
 
Reported: 2023-03-15 09:15 UTC by deadmeu
Modified: 2023-12-01 13:43 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In:

Attachments
Add an attachment

Note You need to log in before you can comment on or make changes to this bug.
Description deadmeu 2023-03-15 09:15:32 UTC 
SUMMARY
When a window (such as Firefox using its custom decorations) is snapped to the side of the screen, moving the cursor to the top tabs, touching the edge of the window, causes the cursor to enter into a resize window state.

This is incredibly annoying to deal with as the tabs are quite small and whipping the cursor to the top of the display, touching the tab and window edge, is typically a convenient way to select the tab.

I think this was introduced with the Plasma 5.27.3 update as I did not notice this prior to updating. It could potentially be an issue with Firefox but I get the same behaviour with VSCode when trying to access its top bar menus. Additionally, the scrollbar edge in VSCode also forces the cursor to enter the resize state, but this does not occur in Firefox (I'm not sure whether this was an issue with VSCode prior to updating Plasma).

This issue does not occur when the window is full-screen.

Note: I'm unsure which product/component would be responsible for this issue.

STEPS TO REPRODUCE
1. Configure Firefox to use its own custom title bar.
2. Snap the Firefox window to either the left or right edge of the screen.
3. Open a few tabs and try to swap between them by sitting the cursor right at the top edge of the tab.

OBSERVED RESULT
The mouse cursor enters the resize window state.

EXPECTED RESULT
The mouse cursor acts like a regular cursor and allows the tab to be clicked normally.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 5.27.3
KDE Frameworks Version: 5.104.0
Qt Version: 5.15.8
Kernel Version: 6.2.6-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 24 × AMD Ryzen 9 3900X 12-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX 7900 XT
Manufacturer: ASUS
Comment 1 Nate Graham 2023-03-15 20:14:18 UTC 
A few questions:
1. When you say "full-screen" do you mean actually full screen, or mazimized? They're separate states.
2. Does the issue go away if you force the affected XWayland-using apps into their native Wayland modes?  You can do this for Firefox by adding MOZ_ENABLE_WAYLAND=1 to /etc/environment, rebooting, and then starting Firefox
3. Are you using any screen scale factors on your system that aren't either 100% or 200%? If so, does the issue go away for XWayland-using apps when you do change the scale factor to 100% or 200%?

All of these questions are to help me understand if the issue is Bug 459373, or something else.
Comment 2 deadmeu 2023-03-16 04:11:59 UTC 
(In reply to Nate Graham from comment #1)
> 1. When you say "full-screen" do you mean actually full screen, or
> mazimized? They're separate states.
Sorry, I mean maximised. I've just tested proper full-screen (by pressing F11) and maximised in Firefox and VSCode and found that in Firefox, full-screen and maximised have the same good expected behaviour, but in VSCode going full-screen causes the scrollbar edge to have the issue. When Maximised, VSCode exhibits the good expected behaviour I described earlier.
> 2. Does the issue go away if you force the affected XWayland-using apps into
> their native Wayland modes?  You can do this for Firefox by adding
> MOZ_ENABLE_WAYLAND=1 to /etc/environment, rebooting, and then starting
> Firefox
I have already enabled Wayland in Firefox (confirmed by checking in about:support that Window Protocol = wayland). VSCode's behaviour seems to be identical regardless of whether it's running under XWayland or Wayland natively.
> 3. Are you using any screen scale factors on your system that aren't either
> 100% or 200%? If so, does the issue go away for XWayland-using apps when you
> do change the scale factor to 100% or 200%?
No, I use 100% scale.
> All of these questions are to help me understand if the issue is Bug 459373,
> or something else.
I don't think this is the same as Bug 459373 and I really don't think this was an issue prior to me doing a system update a couple of days ago.

It might be worth noting that I have installed Firefox as a Flatpak, but VSCode was obtained from the Arch repo. Both of these were recently updated alongside me picking up the Plasma 5.27.3 update but I don't think they would be responsible for this issue as it appears in multiple programs using custom decorations.
Comment 3 deadmeu 2023-03-16 04:22:01 UTC 
Here's a video of the issue: https://streamable.com/fy6acq
In the video, I start by showing the expected tab switching behaviour when Firefox is maximised, then full-screen. Then I snap Firefox to the edge of my screen and try to switch tabs as before but am unable to do so.
Comment 4 Nate Graham 2023-03-27 19:00:21 UTC 
Can reproduce the issue of being able to resize tiled windows from the top window edge.

The thing with VSCode and the scrollbar is probably something else, maybe an issue in VSCode itself.
Comment 5 deadmeu 2023-12-01 13:43:50 UTC 
This one has been quite annoying for me over the months and I wish there was something I could do to mitigate it...

Is it possible to disable the ability to resize windows from the top/all edges? If anyone has any ideas please leave a comment as this has been driving me nuts 😬.