When using the "Extrude solid" tool there is no preselection, ie, the tool is selected then you have to select the closed curve. However, If I have text selected and then select the "Extrude solid" tool, it appears VC attempts to extrude the text. This then makes attempted rotating of the view very slow, with the cursor keep changing from the rotate to the wait pointer. Going to the Undo does show an entry for the extrusion and the concept explorer shows the text change from text to a part. Making an Undo does then resolve that, but VC should not even be attempting to extrude the text anyway.
(Note: this is also a problem if you select the text after selecting the "Extrude solid" tool)