Thanks! :) Glad you are enjoying the program! The bug you describe sounds like maybe the 3d view is losing focus when interacting with the side panel and thus the keyboard shortcuts associated with that gets disabled. You can try to enable the "mouse auto-focuses the panels" option in the Edit > Settings > General panel, to see if that helps you. You can also press the ` key to focus the 3d view, or hold spacebar before clicking the 3d view. If it doesn't solve the problem, then I'll have to try and see if I can reproduce it. Maybe it is related to a non-english keyboard or language you are using. If so, let me know which one and what operating system you are using, and any other info you think will help me reproduce the issue.