Ghc-mod: how to fix the pane with the error and build info as a vertical panel on the side?


i use a wide screen and would like to have the panel for the error and build output fixed as a vertical pane of fixed size. i achieved this once, but cannot replicate it – demonstrates that it is possible. i installed term3 but do not see how this would help (per answer to a question before: console/terminal pane on side).

any suggestion what sequence of action creates a vertical error/build pane?
thank you!