Add right-click context menu item to select end point of a column-block to improve editing productivity. This would make it possible to define column blocks with one hand, using just three clicks of the mouse or trackball.
A left mouse-click selects start point as usual; move cursor to end point without assistance of the keyboard, right-click to define the end point and simultaneously raise the context menu, then left-click "Select Column" item from menu.
This feature might be added by means of a plug-in that is installed by default, if Geany allows plug-ins to modify the context menu. A plug-in would give this capability to existing and older releases. If it requires a change to the base code, it could be added as a checkbox to enable the feature in a future release of the Geany Preferences dialogue, as some users may not care about column block editing and would prefer less context menu clutter.