(Thought I had posted this before but couldn’t find any reference so sorry if repeat - just happened to me again, by mistake)
In SB, click on data tab to display data grid for a table with an XMLTYPE column, before data is displayed (which can sometimes take quite awhile), click on another table. Toad then becomes unresponsive, not doing anything on my PC or on the database. Clicking again on anything else, pointer becomes an hourglass - seems to never return so have to kill it.