Is there a way to add extra icons in harness container header? Whenever I select a cell to add another icon, I could see all the options disabled. Is it handled at skin label where we can define how many icons can be added at design time?
The icons for the expand / collapse container formats are defined in the skin
You can have different icons for expand / collapse using different container formats. In the dynamic layout property panel, pick the correct format to get the correct icons. Make sure to add a header title and make the container format collapsible.