Those neat, useful little hidden capabilities, goodies, and shortcuts in Squeak's User Interface – what they are, where to find them, how to use them. See also Squeak bons mots and Using the editor.
Use shift+right-click in windows/panes with menus that cascade to "more..." submenus to pop up the submenu directly.
To apply syntax coloring to code in a browser text pane: hold down a shift key, right-click to get the menu, select "pretty print", then let go of the shift key.
Use shift+click on the Squeak desktop to pop up the "find window" menu for the project. In Morphic it lists open windows first, then a separator line, then minimized windows – and windows with input that has been changed but not saved are shown in red.