Background bleed + border inconsistencies in VIM, tmux, iTerm2 on OS X using solarized-dark

Question

I describe two cases below which present oddities that I can't really wrap my head around. I suspect it has to do with how many colours are allowed. I also think that the issues (tmux background bleed and VIM borders) are actually two separate issues, but I have not been able to get them to occur simultaneously. Any help would be greatly appreciated!

Case 1: VIM only (in iTerm2)

The solarized dark color scheme appears as shown on the official solarized website. However, the pane borders in VIM are absent and lack color. For good measure, my .vimrc is open on the right pane.

Case 2: VIM + tmux (in iTerm2)

The background is almost always brighter than in Case 1 except for some darker areas (which is what I expected to see in the first place.) On the other hand, the pane borders in VIM appear normal and coloured. My .tmux.conf is open on the right pane.

Details

VIM was installed via Mac Ports

• OS X 10.9.1
  • Upgraded from Mountain Lion
• iTerm2 1.0.0.20130622
  • iTerm2 -> Preferences -> Profiles -> Terminal -> Report Terminal Type: xterm-256color
  • Installed solarized theme
• VIM 7.4
  • Installed via Mac Ports
  • Installed solarized theme
  • .vimrc in first image
• tmux 1.8
  • Installed via Mac Ports
  • .tmux.conf in second image

UPDATE 1: I have managed to fix the background bleeding issue because I found this question on StackOverflow. Jason Yeo's solution worked for me (the accepted and most upvoted solution by Seyeong Jeong did not work for me.)

Aten

iTerm2 -> Preferences -> Profiles -> Terminal -> Report Terminal Type: xterm-256color is reported when in iTerm. But when you launch tmux is it still showing the same? – Lastminute