Double-check that you really have no tools selected. If you look at this screenshot, then it may look like you have no tools selected (because 'Tools' shows a minus). However, it actually has one of the tools selected (the crop tool) and not any of the others. That is why you see a minus. If there are really no tools selected at all, then you should see an empty checkbox. Click on the < at the right to open up the tools so you can select/deselect individual ones.