Bug 505067

Summary:	Plasma desktop and widgets respond slowly to images from web browsers being dragged over them, causing rapid drag-and-drop motions to fail
Product:	[Plasma] plasmashell	Reporter:	Tech-Tac <im.tech.tac>
Component:	generic-performance	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	CONFIRMED ---
Severity:	minor	CC:	john.kizer, nate
Priority:	NOR	Keywords:	efficiency-and-performance
Version First Reported In:	6.3.5
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Rapid drag-and-drop from browser to desktop not working

Description Tech-Tac 2025-05-31 16:08:21 UTC

SUMMARY
Drag targets like the Show Desktop widget on a panel, or the desktop view itself, react very slowly to large files (a 22mb image in my case) dragged over from Firefox (not sure about other browsers), whilst the same doesn't happens with large local files or small web images.

STEPS TO REPRODUCE
1. Go to a 4k wallpapers site
2. Find a full size preview of a large one
3. Attempt to drag it into the desktop or through a widget

OBSERVED RESULT
Slow reaction with the no-move cursor

EXPECTED RESULT
Slowliness should at least begin to take effect when I drop the file, file data is irrelevant to most widgets until I take action on it.

SOFTWARE/OS VERSIONS
Arch Linux, Kernel 6.14.9
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.14.0
Qt Version: 6.9.0

ADDITIONAL INFORMATION
DDR3 RAM
3.2GHz 8 thread processor

Comment 1 Nate Graham 2025-06-03 22:36:39 UTC

Cannot reproduce on current git master with a system with the following hardware characteristics:

Processors: 16 × AMD Ryzen 7 7840U w/ Radeon™ 780M Graphics
Memory: 16 GiB of RAM (14.9 GiB usable)
Graphics Processor: AMD Radeon 780M

Comment 2 John Kizer 2025-06-15 06:45:18 UTC

I can reproduce on current git master - the size of the image doesn't seem to matter in my case, but it does cause very rapid drag-and-drop motions from either Firefox or Vivaldi to the Plasma desktop to not work.

Thanks!

Comment 3 John Kizer 2025-06-15 06:45:54 UTC

Created attachment 182277 [details]
Rapid drag-and-drop from browser to desktop not working

Comment 4 Tech-Tac 2025-06-15 07:15:00 UTC

I'm definitely on the lower end side* and the time it takes for the system to react to dragged files seems noticeably proportional to file size, even the little thumbnail that appears when an item is dragged takes time to load, from memory to memory that is. The whole plasmashell seems to briefly freeze on large dragged files but it's not a serious problem.

*: the lower end in question:
CPU: AMD A8-5500B
RAM: 8GB DDR3 (7 usable)
GPU: (integrated) AMD Radeon HD 7560D