Bug 410378

Summary: Can't use Spectacle's Area dropdown with mouse on display that isn't the top-left
Product: [Applications] Spectacle Reporter: skierpage <info>
Component: GeneralAssignee: Boudhayan Gupta <me>
Status: RESOLVED WORKSFORME    
Severity: normal CC: kde, nate
Priority: NOR    
Version First Reported In: 18.12.2   
Target Milestone: ---   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: Spectacle spans my upper and lower (primary laptop) displays. Note no dropdown menu highlight.

Description skierpage 2019-07-30 00:05:42 UTC 
Created attachment 121826 [details]
Spectacle spans my upper and lower (primary laptop) displays. Note no dropdown menu highlight.

SUMMARY
On my X11 Fedora KDE Spin desktop, clicking with the mouse on Spectacle's Area dropdown field brings up the menu (Full Screen (All Monitors), Current Screen, ... Rectangular Region), but I can't highlight or choose any of its items with the mouse. But this only happens on my primary laptop monitor, the Area dropdown menu works fine with the mouse on my secondary monitor.

STEPS TO REPRODUCE
1. Plug external monitor into laptop, in the Displays System Settings Module configure it as second monitor.
2. Start Spectacle. It should appear on the primary laptop display, otherwise drag it there.
3. With mouse, click on the Area: dropdown, try to choose from the menu.
4. Now drag Spectacle to the external monitor and repeat step 3.

OBSERVED RESULT
On my primary (laptop) monitor, the dropdown menu appears but the items don't highlight as I move the cursor over them and clicking them does not choose the item or dismiss the menu. But it works fine on my external (secondary) monitor. Other drop-down menus in Spectacle ([Help v] [Tools v] [Export v] [Save As... v] work fine.

EXPECTED RESULT
The dropdown menu should work on both displays.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.15.5
KDE Frameworks Version: 5.59.0
Qt Version: 5.12.4, using xcb

ADDITIONAL INFORMATION
The workaround is to drag Spectacle to the second monitor, or use the cursor keys.
My external display is an Acer B243PWL 1920x1200 over DisplayPort and my laptop screen is Thinkpad T460 1920x1080 (i.e. both have the same horizontal resolution). System Settings > Displays > Scale Display is 1.1 for both monitors. Windows have the same number of pixels on each display (see the screenshot with Spectacle spanning both displays), they appear larger on the external display because it's bigger.

This sounds a bit like bug 363548.
Comment 1 skierpage 2019-07-30 00:21:41 UTC 
I fiddled around in System Settings > Display, clicking Apply after each change:
+ If I disable (uncheck Enabled) external display, Area menu works with mouse
- Area menu still broken on laptop if I make external display the primary.
- If I position the external display below or to the right of the laptop screen, then Area menu works with mouse on laptop display and not external (behavior switched). If I position the external display above (as I initially reported) or to the left of the laptop screen, then Area menu works with mouse on external and not on laptop.
Comment 2 Nate Graham 2019-08-05 00:54:39 UTC 
Ugh, probably some deep X11 weirdness. I know that having the origin point in the top-left corner corresponding to the primary screen is important for various raw X11 things.

Does it happen when you use Wayland?
Comment 3 skierpage 2019-11-03 23:52:13 UTC 
I'm now on a newer version of KDE (Plasma 5.16.5), Frameworks 5.61.0), and I can't reproduce this bug, the mouse operates everything fine on both monitors.

(In reply to Nate Graham from comment #2)
> Does it happen when you use Wayland?
I didn't try on Wayland before the bug went away, sorry.

Operating System: Fedora 31
KDE Plasma Version: 5.16.5
KDE Frameworks Version: 5.61.0
Qt Version: 5.12.5 , on xcb
Kernel Version: 5.3.7-301.fc31.x86_64
OS Type: 64-bit
Processors: 4 × Intel® Core™ i5-6300U CPU @ 2.40GHz
Memory: 7.6 GiB of RAM