>The only problem now is that the CheckBox seems to be disabled. I had already checked the ReadOnly and Enabled properties of the CheckBox in the Column, in the Grid.; both properties were set to their default values, i.e., ReadOnly=.F. and Enabled = .T.
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>I cannot understand this. The cursor into which the user would enter this information is a writeable cursor, since I used the "Create Cursor" command.
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>With these settings, why can I not write a Check Mark into the CheckBox?

Just two days ago (look at the other thread about checkboxes) I tried this and the checkbox turned out to be readonly when addobject()ed to the column. Just add the line

grid.column.checkbox.readonly=.f.

after the line where you set it to visible, that should do it.

It's a VFP bug, IMO - and from that other thread you can well see how easy it is to get a checkbox in the grid to misbehave.