I have script that sets this OnKey command then activates another open Excel Application window with an API Activate and uses SendKey commands to display the Find dialog to search for matching value.

The problem is when you activate the main Sub procedure "GoToFind()" the second time using the key combo Ctl+Tab, the Ctl key acts like it is still pressed when you select the original window. It acts like the Ctl key is still pressed until you press the Ctl key one extra time. (On the first run the Procedure is activated by the toolbar button which sets up the shortcut key command for ease of use)

The Procedure "GoToFind()" operates in 2 modes. If there's 2 Excel App windows open it goes to the open app window which is not active. If only one app window is open it goes to the Next Workbook Window in the same Excel App. So it still sets the key combo but there is not a problem as long as the same window remains the active window. The problem is related to changing application windows while the script is executing.

I don't think there's an easy answer to this, exept maybe tell the user to press the Ctl key again after using the shortcut method to activate the process.

Sub SetWinShortcutKey(strProcName As String)
  ' Set Ctl+Tab Shortcut
  Application.OnKey "^{TAB}", strProcName
End Sub