It may seem a rather stupid question but after I import vocals (.m4a) into Audacity everything works perfectly for a while, but after five-minutes-ish in the toolbar (file, edit, view, etc) some of the options goes blank (like save project, stereo to mono and others), and I can’t click on them. Same with all effects. I’ve tried clicking on the track, selecting some parts, not selecting, etc but nothing works.
Click the yellow Stop button when you want to edit - Audacity doesn’t let you edit while recording or playing audio, or when paused. If you want to stop and set the cursor at the stop position, you can use the SHIFT + A shortcut. You can use the menus after using SHIFT + A.