I've been developing within the PowerApps editor for a few weeks now, and this is a constant gotcha that's getting really annoying to work with. Often I have to write somewhat complex chained formulas/function calls within the formula bar. To do so, it makes sense to stretch the formula bar to fit the function calls into multiple lines for cleaner readability and editing. Unfortunately when I resize the formula bar, it overlaps the rest of the editor window, so if I'm editing, say, a formula for a button being occluded by the bar, I'll lose focus at some point, have to resize the bar smaller to see the button, re-click the button so I can get to my formulas again, re-size the formula bar large again, and continue working on the function calls.
Here's an image to illustrate:
A future version of the editor where you could resize the whole top bar while downsizing the editor view so this doesn't happen would be very much preferable. If you don't want to make this default behavior, just a toggle option for this would help my dev workflow a ton.