I'm trying to figure out what the best way might be to have a TMSFNCGrid as cell editor. I defined a TTMSFNCToolBarButton as editor and defined a TMSFNCGrid as its DropDownControl. Its works so far. To define a TMSFNCGrid as cell editor directly is also possible, but then the main grid tries to show the cell editor grid inside the small grid cell, so I thought about the solution with the ToolbarButton.
playing around with some of the build in editors I noticed that for example when using etSpinEdit, etDateEdit or etMoneyEdit I can jump over the cell/column by pressing ENTER or TAB but not over cell/columns with an etComboBox or etCustom editor, where the cells/columns with set to etCustom are throwing an exception. Back to my favorite topic, cell navigation ;-)