Context menus or right-click menus display a list of commands next to the cursor when you right-click. When the Quad is active, hold the right mouse button a bit longer (= long right-click).
The content of a context menu depends on the current entity or selection set.
When the Quad is not active and nothing is selected, a right-click repeats the most recent command. Hold down the right mouse button a bit longer to display the context menu.