This page lets you control exactly what all three mouse buttons do in a Power mode file display. You can select actions for what happens when you click on a file, and also what happens when you drag and drop files with each of the three buttons.
For each of the three buttons, the options for clicking are:
Some button modes that don't show a context menu explicitly also support showing one if the button is held down for a certain amount of time; the Context menu after… option lets you configure this time in milliseconds.
The options for drag and drop are:
The Range selection in select and toggle modes option lets you enable additional keyboard support for range selection with certain mouse button choices. Normally, you select a range of files in Power mode by clicking and dragging with the mouse. The options here mean you can also select multiple files by clicking the first file and holding Shift, Ctrl or Alt while clicking a second file to select everything between the two.
The range selection options affect buttons set to Drag select, Partial toggle, Full toggle, and Select only. Buttons set to Auto-deselect and Context Menu (auto-deselect) always support (only) the Shift key for range selection and Ctrl for toggling individual items (to remain more similar to Details mode).