It will be great to have one launcher of calligra in f.e. icon task manager. One launcher for all calligra application (flow, writer, stage, etc.)
It is a waste a space on bar to have all of them.
F.E. using libre office I am adding only one shortcut (launcher) on task manager, or desktop. And after clicking it, I will get a window with icons of app and I can choose one to open

obviously a work around but you could use a quicklaunch or shelf widget to do this