[SOLVED] Kanban screen shows blank screen after using "Go back to last item"

Hello

The Kanban screen shows just white space after using "Go back to last item" but objects seams to be there because when the mouse is hoowering over the screen the icon pointer change to the "hand".

How to produce the situation:
1) Go to "Planning" --> "Kanban"
 ---> Kanban loads correctly

2) Click on one of the listed Activities the arrow symbolc "Go to item #..."
---> Activity screen will with selected activity will be loaded correctly

3) Click ont the left arrow symbol "Go back to last item" (left top corner)
---> Kanban screen shows only white space but items seams to be loaded to to changing mouse symbol when hoowering over the white space.

Can be reproduced this in Firefox and Edge.
Behaviour can also be seen on  the DEMO

Regards