WORKAROUND:
1) Start with data compare window maximized,
2) Resize Toad’s main window to simulate a small desktop area.
3) Un-Maximize the data compare window
4) Move the data compare window down a bit by dragging from its top toolbar
5) From the top of the data compare window, resize it so it is taller.so that it is taller
6) Now you can scroll in Toad’s main window to get to all of data compare.
STATUS:
This issue is fixed in Toad for Oracle 12.11. This version can be downloaded from the downloads section of our website, which you can access by clicking here.