SideBySide2: Disable browser selection and rely on CM3

Users can select line numbers from the gutter by starting a selection
drag within a padding element.  This is annoying because the user
really wanted to select the code from CM3 and skip the line numbers.

Use CSS and the nonstandard *-user-select rules to disable selection.
On Chrome this prevents a drag starting in padding from creating any
sort of selection, forcing the user to drag in code instead, which CM3
picks up and manages.

http://stackoverflow.com/questions/826782/css-rule-to-disable-text-selection-highlighting/4358620

Change-Id: I412262bc1db000aef079644e73f860ad850663a0
2 files changed