Flamegraph is not repainted correctly when zooming out

[Waqar144]

Describe the bug

See the attached video. It is easier to see the problem than describe it:

https://github.com/KDAB/hotspot/assets/7696024/2cdc4d1b-d0f4-4ee1-8acf-5b98becc46f8

To Reproduce Steps to reproduce the behavior:

1. Open perf.data.perfparser.tar.gz
2. Zoom into KateApp::init() as much as possible
3. Zoom out using the "Go back in symbol view history (Alt + Left)" button in the top left corner of the app one step at a time
4. See dirty regions after 2nd or 3rd step

Expected behavior Regions are cleared properly

Version Info (please complete the following information):

• Linux Kernel version: 6.6.19-1
• perf version: 6.7-1
• hotspot version (appimage? selfcompiled?): master (self compiled)
• if self-compiled hotspot, what version of elfutils: 0.191-1