With the column tool the user can (what a surprise -:)
create columns.
After adjusting some parameters in the context menu
simply left-click on any surface.
In a free space a column with defined parameters and height is created, the direction (up/down) is set in the context menu.
When the user creates a column 'under' another element, it's height will be adapted to this 'ceiling'.
Here an additional adjustable column top element is created.
Again, when direction 'down' is selected, the column can be drawn from any point down to the bottom (next visible element).
Context-menu:
