Bug: Mouse events captured by invisible window preview

[binarynoise]

After hovering a window to show the thumbnail/preview, the preview continues to intercept mouse events even after it is no longer visible.

Steps to reproduce:

1. Hover a window to make the preview/thumbnail appear.
2. Click the preview to bring the window to the foreground.
3. Try to click or scroll over the area where the preview was shown:
   • Clicks in that area now have no effect
   • Scrolling in that area triggers the default preview action (open/restore/maximize/minimize)
4. Manually closing the preview by clicking the application icon instead of the preview seems to fully close the preview window, so mouse events aren't intercepted any more.

The problem started around the time Cinnamon 6.6.
The same effect appears when only displaying the list of window titles.
It looks like there is something missing when the preview is dismissed by selecting it, instead of getting actively closed.

Screencast:

2026-01-21_22-04-03.webm

This is a follow-up to my report at https://cinnamon-spices.linuxmint.com/applets/view/372

[binarynoise]

Setting fade-animation-time to 0 prevents the issue.

Maybe the onComplete doesn't properly fire here?

CassiaWindowList/CassiaWindowList@klangman/6.4/applet.js

Lines 1333 to 1339 in 6069422

	let time = this._settings.getValue("fade-animation-time")*0.001;
	if (time) {
	Tweener.addTween(this.actor, {time: time, transition: 'easeOutQuad', opacity: 0, onComplete: () => {super.close(false); this.removeAll();}});
	} else {
	super.close(false);
	this.removeAll();
	}

[klangman]

Thanks for reporting the issue. I don't have 6.6 on my main machine yet, but I do have a 22.3 VM I can test on. I'll work on that soon.

[klangman]

I think maybe I need to move away from Tweener and use easing instead.

[DNKpp]

Hello,
I have a similar issue. Since the last mint update (22.3) there is an invisible non-clickable area when I switch windows by clicking on any preview-image. That area is gone, when I just trigger the preview of the app which is causing the issue, but not clicking on the preview.

preview -> mouse-click => issue
preview -> mouse-leave => no issue

[klangman]

I tried to recreate the issue in a 22.3 Virtualbox VM but I can't recreate the problem. Can you guys see anything I am doing wrong?

No-recreate.mp4

[binarynoise]

Interesting, I just booted up the live iso, added CassiaWindowList and could reproduce. I do use VirtManager though but I doubt that makes the difference.

2026-01-24_12-33-50.mp4

[nalmada]

I don't know if it's related or an other bug entirely, but when I open more than 2 or 3 windows off the same app, the thumbnails preview list start to glitch

Screenshot after opening 4 chrome windows and then closing two :

You can see that the thumbnails preview did not shrink to only show 2 windows

Additionnaly I can reproduce this issue main issue : all mouse events in the thumbnails preview area are captured by this applet, including middle button mouse scrolls

When I have 3 instances (windows) of the same app, it even overflow the thumbnails preview list :

[klangman]

@nalmada Did that only start happening after an upgrade to 22.3, or are you on some older Mint?

[nalmada]

@nalmada Did that only start happening after an upgrade to 22.3, or are you on some older Mint?

only since 22.3
Sorry forgot to add system infos 😄

[klangman]

@nalmada Damn... Another issue I can't recreate in my Virtualbox 22.3 install. Fedora Cinnamon spin has yet to move to Cinnamon 6.6 so I am not yet running 6.6 bare metal.

[DNKpp]

Is there any workaround I can use in the meantime? Except removing the extension, of course.

[binarynoise]

@DNKpp

Setting fade-animation-time to 0 prevents the issue.

It's in the last tab of the settings (Advanced - Fade animation effect duration)

[DNKpp]

@binarynoise Setting this to zero, removes all preview thumbnails for me. I think, I'll just leave it as-is and wait for a fix then.

[ValensHawke]

Tossing my name into the hat as I am having this problem as well.
Kernel: 6.8.0-100-generic arch: x86_64 bits: 64 compiler: gcc v: 13.3.0
Desktop: Cinnamon v: 6.6.7 Distro: Linux Mint 22.3 Zena
base: Ubuntu 24.04 noble
At first, I thought this was actually an issue with Plank Reloaded (which I did report to the author and you can see me and him trying to troubleshoot that at its repo), then it dawned on me that the issues I was having at the bottom of Firefox where my mouse clicks wouldn't register might be related to this. Once I figured that out, I can usually untrigger it by clicking on one of my many windows, usually the last one I used or clicking on the all buttons on the panel, usually one of them will release the mouse.
The aforementioned reducing fade animation effect also prevented any previews. I have since changed to 20 milliseconds to see what happens.