Calling wxGrid::{Insert,Delete}{Rows,Cols}() from wxEVT_GRID_CELL_CHANGE
event handler resulted in infinite recursion because it tried to hide
the grid editor control again, which resulted in another CELL_CHANGE
event being generated and so on.
Break this infinite recursion in the usual way, i.e. by updating the
state of wxGrid before invoking the user-defined event handler.
This required separating SaveEditControlValue() in 2 functions, the main
one retaining IsCellEditControlEnabled() check for compatibility, and
the new DoSaveEditControlValue() that can be called even after disabling
the editor.
Closes#2287.
Closes https://github.com/wxWidgets/wxWidgets/pull/1540
be53b3fb20