You can't do full control of all divider lines at all levels, but you do have some flexibility by using different dividers on cells, panes and doing divider lines at different levels. In my example, I put a thin gray border on the cells, a thick gray border on the panes. Then I put divider lines on rows and columns. The red divider on rows is at the same level as the pane, so it overrides it. The green divider on columns is at the years level, so the gray divider on quarters still shows.
When you format borders, there is a slider for the level that lets you choose where to put it. If you don't have nested dimensions on rows or columns, then there won't be so many levels to choose from.
I've attached the workbook for my example.
Austin, thanks for this, it is very informative. I've always struggled with Tableau to get any organizational border scheme, but this will make it a lot easier. Now if we could only get that last line on the far left to complete the outside box and have the vertical lines run all the way to the title box border we'd have a complete, nice looking grid. But thanks again this will really help.
Excellent! That's what I was looking for.
This is where I mention that I actually have done this before (the first example I posted above was mine!). I just forgot how