I use the latest version of TOAD - 12.10 and just came across very annoying problem.
When i select a table in SB and then click on constraints TAB, it gives me the following error (attached).
during subsequent clicks the problem goes away until SB is restarted and then the error shows up again.
If you click on the “click here” on the dialog that you sent a picture of, it will give you the call stack. The picture is nice but of no real use in diagnosing the issue. If you could send or attach the call stack, we should be able to help.
Try right-clicking in the grids of SB-Tables-Constraint and choosing “Reset Columns”. (You might have to click on a table with no constraints to do that).
If that doesn’t fix it, then please send the call stack as Greg requested.