Matrix with subcategories

[Igula]

Hi Guys,

How can I create subcategories to this matrix?

 

Subcategories are under each country of course. Tries as described here but couldn't find this option. Not sure where exactly to click to get to this.

[Igula · Accepted solution]

Found by myself today. Well explained here: 

https://www.google.com/search?q=matrix+visual+how+to+add+expand+buttons&oq=matrix+visual+how+to+add+...

[Greg_Deckler]

@Igula So generally you would add another column into the Rows field well for your matrix.

[Igula]

Not exactly. I meant this kind of visual, when I can click + and the list in expanded under each category, like here I can furtherr expand Lead, Qualify, Solution,... So what I do not know is how to add tehe subcategories with expansion buttons (+)