When opening a segmentation (just 0/1 so it's displayed in red+transparent) the behavior of MITK is different depending on whether the segmentation tool is open or not. If it is closed, the segmentation is displayed as red area. If it is open the segmentation is displayed as a red contour. This should be consistent.

In my opinion a contour is a very bad way of presenting a segmentation. Yes it works for organs (LIver etc) but when viewing convoluted structures it is impossible to see which part is supposed ot be inside and which is not. Please make 'red area' always the default. If needed you can still add a toggle somewhere to switch over to contour mode for those that need it