I am working on a spreadsheet with some protected cells and was told that I
might insert or delete as many rows between a range (e.g. line 10 to line
20).

I got no problem to insert rows by selecting ROWS from the INSERT menu, but
I couldn't use the "Insert Row" icon from the toolbar since it was disable
(the icon in gray color). However, I couldn't find a way to delete the rows
I just inserted.

Question:
1) Is it possible that the "Insert Row" icon can be functionated in the
protected spreadsheet?
2) Is there a method to delete rows in the protected spreadsheet?