1) Smart Navigate tries to do everything. Depends where the cursor position in current moment. Go to matching brace, to pair tag, to include file or to label. Done to not force people to remember all shortcuts. Always try SmartNavigate and Hippo would try to understand what you want

1b) This depends from syntax schema. What is defined as pair symbols in <OpenClose>...</OpenClose>. If symbol is inside and this does not work - this is a bug. But does not work for symmetric pairs (like "" and ''), because it is difficult to find out if this is a close or open one.
2,3,4) I would combine this 3 requests in one. How to select to drom current position till some text. There are tow ways to achives this. First. Use search dialog and option Extend Selection. Second. Use Anchors. First
Set Anchor in current position (F7) then use
Smart Navigate to go to matching brace or pair HTML tag and then use
Select From Anchor (Shit+F7) command to select text between.
Set Anchor can be found in
Navigation menu, and Select Form Anchor in
Edit->Selection menu. For dot or comma you need to do the search instead of
Smart Navigate. If you have better idea how to merge these 3 actions in one clever command - suggest
