Select Linked extend with double click hotkey

In the UV editor, I am trying to make it so that double clicking invokes “select linked”(or “select linked pick”) and shift double clicking does with same with the “extend” option. Basically I just want to double click to select islands(and shift double click to extend that selection).
While I was able to get the select linked double click working, it could not get the extend version of it to work. I had to use “Select Linked Pick” to even get it to do anything, but It seems that the default extend select behavior(mapped to shift click) is interfering with my double click select linked hotkey.

Is there a way to get shift extend select linked working in UV editor while keeping the existing shift click for normal selection?

Old topic, same question. Applies to both UV editor and 3D view/Mesh. Any ideas to get this working?