Beside the simple editor with maximum possible helpers and hints for the beginners, which indeed can have even more popups as now (perhaps you could add the checkbox option there "[ ] Do not show this message again"),
the normal (or possible future expert editor that could have some more degree of freedom like blockmixing

- There should be also some shortcuts for the Macroblock mode that do not need the display of a dialog box.
Just one example: if you want to delete may different blocks of a map at once, it is helpful to mark them all with the macroblock cursor. Then instead of cutting them out, one can press the DEL key, because when you cut out, you have to click on the x to clear the selection afterwards.
Surprisingly if you press the DEL key, there is a dialog popup "clear selection?", which is somehow redundant, as there is the undo available as well for this operation, right? (only rethoric question here

Such things slow down the fluid editing a bit.

Same for the case where there is an invalid macroblock selection.
Instead of a popup, there could be a red text be written on the bottom right place where you display shortcuts and functions anyways, and some "meep" error sound which is not too much annoying

Perhaps just make this place there a bit larger, or have the text display on top of the screen as kind of HUD signal.
- quicksave is missing (e.g. using CTRL+S or just S), or you could put a additional disk symbol, as the actual one rather behaves like "Save as".
- A shortcut for a quick shadow calculation (or using the last setting) was also already requested by someone I think
- And finally a list of all available key shortcuts would be really nice at the help page ([?] icon, or H key).
For the time beeing, it also could be added to the documentation in github (I know I could edit it there, magnetik

