'WM_LBUTTONUP' tag RSSI was recently using a ComboBox control with the DropDownStyle set to Simple, effectively turning into a combined text box and list box.
However, when I wanted an action to occur on double clicking an item in the list I found that the control doesn't actually offer double click support. I suppose I should have just ripped out the combo box at that point and went with dedicated controls but instead I decided to extend ComboBox to support double clicks.