Having a large table with about 400 (only number and varchar2) columns with some thousands of rows in it and having:
1. checked View | Toad Options ... | Schema Browser | Data and Grids | Save layouts
2. used the function 'select columns' to only have displayed about 10 columns from the 400 columns of the table
==> After this toad isn't usable for about some minutes and then the correct result (with the Save layouts and set of columns) shows up.
(The amount of rows doesn't seem to make any big difference)
It is possible verify the issue with the timestamps of the SQL Monitor and also in the SQL Trace file
(This issue doesn't appear, when using the SQL editor using the SQL Statement gaining the same result)
Waiting for a fix to be released in a future version of Toad for Oracle.