Created attachment 125476 [details] Screenshot showing problem. Sometimes after opening/closing applications I get a huge gap in the icon only task manager. I'm not sure whether it's a problem with the panel or the widget, but I think the panel since I've never seen it occur with a maximized non-hiding panel. My panel is set to the smallest minimum width, largest maximum width, centered, and on auto-hide. See the screenshot.
I can't reproduce this anymore on Plasma 6 Wayland, and I have a memory of it being fixed at this point in the past. So let's consider it fixed!