Fixing an overfull measure

Suppose I am depositing quarter notes with a mouse, and forget one. I shift the Entry tool to the Insert mode and insert the forgotten note. I then proceed, accidentally overfilling the measure (with, say, six quarter notes altogether). (I had actually intended to add notes to existing notes to form chords.)

MuseScore nicely warns me of this situation with the little "overfull" sign above the right end of the measure.

How can I delete the improperly-added notes? If I try and do it in any of the obvious ways, the deleted notes are replaced by rests, nit what I want, and leaving the measure still overfull.

The User Guide (p. 199) suggests that when the Input tool is in the Insert mode, one can both insert and delete notes (and that the measure would "close up" around the deleted notes. But it gives no example of how to delete notes.

That same passage says that, in using the Input tool in Insert mode, "Measure duration is automatically updated as you go." Then how could I overfill a measure?

Thanks.

Doug