Multiple button selection, main and sub menu

Surprised I've not been able to find an answer on this but here goes...

I have a main menu at the bottom of my screen with various buttons for inventories, options, etc. Say for instance I select Inventory the main menu button becomes highlighted, I want it to remain highlighted as I interact with the items in my inventory but it's currently becoming deselected.

I understand why this is happening, and I'd assumed the solution would be to have different event systems for different areas of the navigation, but that doesn't seem to be an option. Is there an easy way to achieve this or do I have to write some custom logic to handle the navigation/highlighting of different sections of the UI menu? Seems like too standard a thing to not have some sort of built in solution.

 

Necroing this for 2018 and 2019 since I couldn't find any solutions/approaches around.

How to keep a top level menu option still highlighted while interacting with the buttons in the related sub menu (similar to how the current tab is highlighted in a browser). Otherwise it is easy for user to get lost in navigation if there are sub menus, or windows for interactable content.

 

I am currently battling with this as well. What is the standard approach for this? I can cache the normal button color, change the normal button color to highlighted, then when the button regains focus I can reset the colors but this seems kind of hackish. There has got to be a better way to do this.