Automatic closing of Creo Toolbars

We just installed Creo in the class room, some computers operate correctly, others ( including the instructiors ) will close the toolbar after each operation. That is to say, I open sketcher, draw a line, wish to continue with another line, but the sketching options close. I must click on the sketcher tool everytime I wish to draw a line section. Does anyone know what is going on? It is quite frustrating and makes the software almost impossible to work with.