Feature Request: Ability to collapse/expand category or add category to filter by clicking on/near category name

[mileso]

When viewing the characters of a font in the Character GridView I'd like to be able to "Collapse" the category so that only the category name is visible (and conversely be able to "Expand" the category after it has been collapsed). I'd prefer to click on a glyph adjacent to the category name like in a TreeView but a right click menu would work as well. A simpler version would be "Add to filter" instead of "Collapse/Expand." However, that would require opening the filter drop down to show the category again. Perhaps the "Unicode Category Filters" could use tri-state checkboxes to indicate Visible/Collapsed/Hidden status. Visible/Hidden would still be the only options within "Unicode Category Filters" but clicking the checkbox of a "Collapsed" category would make it "Visible" and "Reset" would expand all collapsed categories.