In the latest update of Power BI desktop, when on-Object interaction from the Preview Features is activated, there is an issue that when you group visuals, you can no longer change the size using the mouse. The double sided arrow will not show. You need to now go to the formatting pane and adjust the sizing there, or double click on each visual independently allowing the use of the mouse when the visual is not as a group.
Here is the link to the question that's already been posted:
community question
Hans-Georg_Puls
on:
Desktop Application Bug?? - PBI desktop applicatio...