There are some staff that can be done to minimize the gaps see the below picture:
first you need to know the the column cell (dimension) is fixed size this mean if you have wide category all the cell will be adjusted to the widest, you can do the following:
1- you can change the alias of the fields make it smaller.
2- you can select the standard fitting that allow you to resize the cells.
3- from the analysis menu select legend then display the size legend and click its context menu and select edit size (then reduce the distance between smaller and larger size) this will reduce the Gaps.
Any chance to remove gaps completely?
I did the following and I still see gaps.