Unused panels are getting displayed in the bottom area
In 43 a lot of (not needed) panels are getting displayed, like "Unit test output", "Debugger". In 42 these were hidden by default until actually used / needed.
Due to the high number of buttons, the lower area is relatively large, and can no longer be reduced in size.
[runtime.version]
version = "43.alpha2"
channel = "flatpak-nightly"
identifier = "43.alpha1-494-g6a6fbc411"