At least in this activity (in could be happening with other activities, also), some controls for opening the big text editor (“<>”) or for choosing a variable (“+”) for the “Command” input text box randomly are present or they ara not shown.
This is annoying and frustrating because when you are used to do it this way you find yourself doing the action but the buttons are not there, forcing you to go to the “Properties” tab to get the same result.