When you select a series of curtain grids, panels, or mullions there is an option in the highlighted "Modify | Curtain Wall Grids" tab:
Click to enlarge... |
In conclusion, the pin that pops up when you select an element is not the ONLY way to pin or unpin things...
**Edit** Or as Paul Aubin and Luke Johnson rightfully pointed out... The default keyboard shortcut for Pin is "PN" and Unpin is "UP" ...