An application sends a ZGM_AUTOSIZECOLONEDIT message to enable or disable automatic column sizing to fit data entered in an editable cell.
ZGM_AUTOSIZECOLONEDIT
wParam = (WPARAM) (BOOL) fEnable; //enable flag
lParam = 0; //not used; must be zero
This message does not return a value.
Automatic column sizing on edit will only happen when the user finishes an edit by pressing the Return key. If a cell is being edited and the user mouse clicks into another cell, the cell that was being edited will not be autosized to fit.
Autosizing of columns on edit is enabled by default.