Pick works like Function if invoked in the context of a window. If invoked in the root window, it first asks the user to pick a window and then executes the command in the context of that window. This avoids annoying multiple selections with complex functions. The command is executed only if the given conditions are met. Returns -1 if no window was selected. See Conditions section for a list of conditions.

This command implies the conditions CirculateHit, CirculateHitIcon and CirculateHitShaded. They can be turned off by specifying !CirculateHit etc. explicitly.