your use of protect for querymode is fine (i do the same thing), you don't have to do a modify to copy:

FOR RMB menu popup to copy:

You want to use getobjectatpointer to see what the user has clicked on and thus what they may want to copy from.  Then you just can do a getitem for columns/computes, and even get the value of text if the object is text.

Since you are talking about querymode, you also need to see if the dw is in querymode when the user is doing a copy since you can't do a getitem in querymode (just do a .copy() )

Also, don't forget about Datawindow.Selected.Data - check that first to get what the user has selected, and only if they have not selected anything do you get the current column

I don't think you can avoid having to do the Modify().

The protect attribute is very nice, since you can use an expression, but what I don't like is that you always have to make sure that the cursor is not in the column when it needs to be protected and also, when ALL columns are protected you cannot do a ScrollToRow().

Instead, I prefer to use the tabsequence attribute. It needs some coding, but once you have coded 3 functions:
1 to initially store all columns and their tabsequences,
1 to set them all to 0
and 1 to restore them to their initial value,
... then it's easy to use. It neither prevents you from having to code though. 

What I do to allow a user to copy a column's contents when "not editable" (protected or tabsequence=0), is to have an option "Copy value" in a right-mouse popup menu.

It's a shame you cannot use an expression for the "readOnly" attribute of a column.

regards