This issue was resolved in TOAD for Oracle 126.96.36.199. The latest version of Toad for Oracle can be downloaded at: http://support.quest.com/support_download/Downloads.asp
1. Close out the Schema Browser.
2. Go to View | TOAD Options.
3. On the left panel, select Schema Browser | Data and Grids.
4. In the right panel, check mark "Save layouts"
5. Re-launch Schema Browser.