Selecting the Session Browser's Top Sessions tab takes a long time to display or at time hangs Toad.
The background query executed when selecting the tab is not completely optimized.
Issue fixed in the current version of Toad. The current version of Toad can be downloaded from: https://support.quest.com/toad-for-oracle/download-new-releases. In this version perform the following:
1. Select View | Toad Options menu option
2. Select Oracle | Optimizer Hints from left side tree
3. Select RULE for All Others drop down and hit OK
The Rule hint will be applied to the underlying query, and hence, will optimize the performance of Top Session tab.