MSFTEventSource now supports an "OpenWhenHidden" flag, true by default.
When false, the SSE will disconnect when a tab loses focus.
- Fixed duplicating eventsource initializer when calling ajax submits on blocks containing the SSE. The traditional SSE client now cleans up the previous instance of SSE on that particular block by assigning a unique ID(provided by the SSE block itself)
- Added a visual cue on design time to better know that SSE is being used on a particular screen/block