It is sometimes inconvenient to take one's hands off the keyboard to use the mouse. Therefore a number of commands may be executed from the keyboard. These include execution of the regular expression, so that one can type, execute, and revise without leaving the keyboard, and commands that pop up and remove the palette, history list, and information such as the list of Unicode ranges.
A list of these commands is available from the Help menu or by typing ^k (Control-k).