When using a viz in a tooltip, the filtering does not work for grand totals. With a simple viz that contains one dimension each on columns and rows and the tooltip set up to show another viz filtered to just those 2 dimensions, the grand total hover always shows everything. When hovering over just the column or row total, ti should filter the tooltip viz to that dimension.
For example, the attached workbook has segment on columns and category on rows. When hovering over Office Supplies and Home Office, the viz correctly filters to those 2 values. However, when hovering over the Home Office grand total, it shows all segments and categories. Ideally, this would show just Home Office for all categories.