Created attachment 137536 [details]
1. Dolphin normal window

SUMMARY
When Dolphin window is maximized, and then unmamiximized, its normal window geometry is not restored. The window in this third step is much wider, and both left and right panels are narrower, requiring manual resizing each time, or closing the window, and opening a fresh window again to have a normal window.

STEPS TO REPRODUCE
1. Open a normal Dolphin window with panels on both sides (Places and Information) 
2. Maximize the window
3. Unmaximize it

OBSERVED RESULT
Unmaximized window is not only much wider, but both left and right panels are narrower.

EXPECTED RESULT
Unmaximizing a maximized the window should restore the window to its original geometry, including position, width, height, and also both left and right panel widths.

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.21
KDE Plasma Version: 5.21.4
KDE Frameworks Version: 5.80.0
Qt Version: 5.15.2