Scrollbars becoming inactive after resize

[humdinger]

This is hrev52827.

Invoke TextSearch on some files and search for a term that'll be found often, so the result list will be large enough for scrollbar knobs to appear.
After resizing the TextSearch window, the scrollbar knobs disappear and contents cannot be scrolled anymore. Mouse wheel doesn't work. The selection can be moved with the cursor keys, but the view won't be scrolled when they move out of the visible view area.

[vidrep]

This describes what is happening on some apps as well. StreamRadio being one example. ​https://github.com/HaikuArchives/Haiku-Radio/issues/5

[waddlesplash]

Will be fixed by ​https://review.haiku-os.org/c/haiku/+/998.

[waddlesplash]

Fixed in hrev52835.

[nielx]

Assign tickets with status=closed and resolution=fixed within the R1/beta2 development window to the R1/beta2 Milestone