Suddenly can't make button selected

Hi

I’m at the moment trying to build my portofolie website, but seem to run into a new problem every 10 minute.

The most annoying one so far is that suddenly I can’t choose “selected”. I have tried to make a new button, but the “selected” function in button properties doesn’t show any more when I’m trying to edit the mobile view…

Also the the fact that you can’t lock shape elements is really annoying. Especially when trying to select and resize button that are close to a shape-line. I can select the button, but I can’t make it the wanted size cause the shape-line is chosen whenever I try to drag the button to the line.

All help is appreciated!