Open ponk issue settings with DARK/LIGHT theme

[TNemecek]

Not sure if this is valid behavior, but i can't switch light/dark mode. It appears to set null when change theme. Theme then looks like set to dark, but nothing happens. Same behavior is with switching back to Light.

nightly build - win
Pharo 12.0.0
Build information: Pharo-12.0.0+SNAPSHOT.build.1539.sha.**688a (64 Bit)

[JanBliznicenko]

Hello, thank you for finding the issue.
While this error should be fixed (on GUI library's side - I have forwarded the problem to its issue tracker pharo-spec/Spec#1632), OpenPonk, unfortunately, does not fully support themes anyway. General GUI items would be switched to the dark theme, but not the main drawing area, there are no dark theme compatible icons and it is overall untested.

You may still try. In order to do that, you need to switch the layout before opening any OpenPonk project for the first time. As long as any OpenPonk window is already opened or still in memory (not yet garbage-collected), the theme would not change properly and cause this error.
If you would like a little experiment, you may also run the garbage collection yourself. Close all OpenPonk project windows (those inner windows inside the application), then in the top menu: Browse - Playground. Write or copy paste there the following code:

OPProjectStorage reset. 
SpNullApplication reset. 
Smalltalk garbageCollect.

Then click on the green arrow "Do it" and try to change the theme again.
Those OPProjectStorage and SpNullApplication parts should not be needed, but I just fixed a few memory leaks caused by these 2 classes holding references to closed OP windows and the fix is only available in current nightly build so far :)