I'm struggling with this issue: I'd like to know options on how to CLEARLY display a sub-filter option in a menu. To better explain: the problem is that I have a set of data that will be filtered based on a certain condition. This filtering happens by default, meaning the user HAS to select a filter condition, or a filter will be used by default, but there's no option for unfiltered results (and this can't be changed). These conditions are CONTENT BASED.
Then, I need to filter these results by a secondary condition. Again, a default filter will be applied -because it's the result of an already performed action-, but this time the conditions are ACTION BASED (meaning that these filters are possible actions that happened on the content already filtered).
While there are some things I'd change on the behavior and flow, I really have no much access to change it, and it works fine for client's purposes. However, I need to come with a visual way to clearly display the set of filters and actions, which in turn will display both graph and tabular data, and at this point, all options we have thought about sub-filtering aren't really convincing me, so any help on this will be really appreciated.
EDIT: what I CAN do is to change order of filters, so I could filter BY ACTION and then sub-filter BY CONTENT. This is how the system works now but I don't like it since I'd rather display results for all kinds of content instead of all kinds of content for a given action. However, I'm open for solutions based on this scenario since it's less work for their developers and they're OK with this process flow
EDIT 2: To clarify, here's what the original site looks like (it's not about books and the filters aren't the same, obviously, but the concept and the layout is the same). Also, I did it bigger aand simpler for demo purposes, but it's a menu bar with a table below
What I did to solve this is to move the second filters as main filters, then display them only at first. Once the user selects one of the actions (read, write or burn) then a bottom paper sheet shows up with the content filter options (novel, essay, poetry). So far, I'm liking this since it's pretty clear, but the client is requesting to have EVERYTHING on display at first sight, so my question is if there's a way to properly apply a sub-filter action (text or icon) on a menu bar