Timelapse UX: custom filter dialog keyboard navigation is difficult

[twest820]

• No shortcuts are available for jumping to a specific data label
• Right arrow works when a row is selected but is sticky since it's captured by the expression column.
• Left arrow doesn't work.
• Up/down arrow works but only on select column.
• UTC offset control isn't a tab stop when enabled (likely an Xceed TimeSpanUpDown bug)
• Controls on a row only have tab stops if they're enabled from the search term being selected. This is awkward and may be by design, but mitigation would be nice if possible

First one is easy enough to address by making the label column the content of the check boxes in the select column. Others need investigation. Left/right arrow don't particularly need to work for moving between controls as tab and shift+tab provide this functionality. Some clean up of current haphazard implementation is desirable if it's not too involved, though.

[twest820]

WPF grid (as opposed to data grid) doesn't particularly support arrow keys. Other issues addressed.