There is automatic detection for e.g. data types when you type in a name. For example, if you specify 'IsVariable' or 'HasVariable', the data type is automatically set to Boolean.
It would be nice to have a similar functionality on the namegiving of a screen, when creating a popup. So my suggestion: automatically set the layout of a screen to LayoutPopup, when you name it "ScreenX_Popup", when it is first created.
I know it is very little effort to make this adjustment manually, but so is changing the data type.