Many times while working in Photoshop I grab a tool and it doesn't do what its supposed to do. It can be frustrating and 99% of the time the cause is a setting in the Tool Options that was changed earlier when working with the tool and is still active. It’s a great disruption to the flow of creativity and can just make you angry.
When you encounter this problem the simplest method to get back on track and continue working again is to reset the Tool to its default setting. You could spend a minute or two trying to figure out what's causing the problem but why spend that time searching when you can simply reset the tool with one click?
To reset a tool, you must first have the tool selected. Then Control-Click (Windows users: Right-Click) on the Tool Preset button in the Tool Options bar.
When you click on this button you will see a small menu appear and you can select Reset Tool to reset the current tool to its default setting or Reset All Tools to reset all the tools to its default setting. Once selected, the tool should act just like the first time you used it.
By using this simple method of resetting your tool with one click you can quickly fix any situation where the tool is not responding correctly and keep the flow of creativity going.
If for some reason this doesn't work you could always try resetting the entire Photoshop program. As you launch Photoshop press and hold Option-Command-Shift (Windows users: Alt-Control-Shift) and you will be prompted to delete the current settings.