Symbols pane shows only symbols for currently open file

[rasmus91]

As the title says.

I found myself wondering today, why it does not show symbols for either:

• All namespaces in the src folder
• All elements that share one of the namespaces of the currently open file (which might be preferrable to the former suggestion)

[jeremypw]

The whole design of the existing outline pane was based on one per open document, so this would take a major redesign, or a separate widget perhaps only updated and showing on demand, to maintain acceptable performance I guess.