Comment 33 for bug 1599453

bzr branch :will create a local branch of a Launchpad branch
bzr pull :will go back to the original Launchpad branch and pull down any new updates
bzr log | less :will show the last commit number of your branch which you can compare against the original branch in Launchpad.

As you can see here: https://code.launchpad.net/~stephen-j-boddy/terminator/gtk3-fix-transparency
You should have revision 1648 as the topmost entry in your log.

If you've committed changes to your local branch the local copy is said to have deviated, and you can't pull new updates from the original. Looking at what you've done I suspect by using commit you have deviated, and now it can't get the new updates somehow, but without literally having a step-by-step with all your commands, it's hard to say.

If you have rights to commit to the the original (in this case I own it, so you don't) then you should do a pull from the original before committing changes to your local branch. This way you can then use...
bzr push :will push new commits from local branch to the original branch, assuming no deviation has occurred.

If you look in gtk3-fix-transparency/terminatorlib/themes/Ambiance/gtk-3.0/apps/terminator_styling.css lines 8-13:

  8 .terminator-terminal-window .notebook.header {
  9 border-width: 0; /* set below depending on position of tab bar */
 10 border-color: shade (@bg_color, 0.82);
 11 border-style: solid;
 12 border-radius: 0px 0px 0px 0px;
 13 background-color: @dark_bg_color;
 14 }

As you can see, exactly the same declaration. You should not need to set it again. Let me know if that gets tabs looking all ship-shape for you.