I seem to be having an issue where the Background blocks wont let me select a different background. Am I missing something?
Sometimes, there are some pending bugs where updating something in one screen do not always immediately update on another:
This bug is similar, but not the same: https://github.com/haroldo-ok/vcs-game-maker/issues/17
I opened an issue for this specific bug: https://github.com/haroldo-ok/vcs-game-maker/issues/143
As a temporary workaround, refreshing the page (generally the F5 key) should force the components to update their internal state, but that's not ideal.