You may be seeing the result of an Event macro. Let's say you wanted to
create this feature: right-click clears the selected cells. Enter the
following event macro in the worksheet code area:
Private Sub Worksheet_BeforeRightClick(ByVal Target As Range, Cancel As
Boolean)
Cancel = True
Target.Clear
End Sub
This produces what you are seeing: the selected cells get cleared and no
right-click menu appears.
Because it is worksheet code, it is very easy to install and use:
1. right-click the tab name near the bottom of the window
2. select View Code - this brings up a VBE window
3. paste the stuff in and close the VBE window
If you save the workbook, the macro will be saved with it.
To remove the macro:
1. bring up the VBE windows as above
2. clear the code out
3. close the VBE window
To learn more about macros in general, see:
http://www.mvps.org/dmcritchie/excel/getstarted.htm
To learn more about Event Macros (worksheet code), see:
http://www.mvps.org/dmcritchie/excel/event.htm