Software Sources (and elsewhere): banner merges with sidebar highlight

[ghost]

Describe the bug In software Sources (and, one might suspect - but I cannot confirm - elsewhere), the banner (when there is one) merges with the highlighted element in the sidebar.

To Reproduce

1. Open Software Sources
2. Change a mirror.

Expected behavior It would be best were the banner (the message about one's configuration having changed) not to merge (colour-wise) into the highlighted item ('official repositories') in the window's sidebar.

Frequency Does the issue happen:

• [X] Always
• [ ] Randomly

Edition (Desktop environment): In which edition is this happening?

• [X] Cinnamon Edition
• [ ] MATE Edition
• [ ] Xfce Edition

Live or post-install: Indicate if this is happening after the installation, or during the live session:

• [X] Post-install
• [ ] Live session

Screenshots

Locale:

LANG=en_GB.UTF-8
LANGUAGE=en_GB:en
LC_CTYPE="en_GB.UTF-8"
LC_NUMERIC="en_GB.UTF-8"
LC_TIME="en_GB.UTF-8"
LC_COLLATE="en_GB.UTF-8"
LC_MONETARY="en_GB.UTF-8"
LC_MESSAGES="en_GB.UTF-8"
LC_PAPER="en_GB.UTF-8"
LC_NAME="en_GB.UTF-8"
LC_ADDRESS="en_GB.UTF-8"
LC_TELEPHONE="en_GB.UTF-8"
LC_MEASUREMENT="en_GB.UTF-8"
LC_IDENTIFICATION="en_GB.UTF-8"
LC_ALL=

Drivers:

Graphics:
  Device-1: InnoTek Systemberatung VirtualBox Graphics Adapter 
  driver: vboxvideo v: 5.2.23 r127298 bus ID: 00:02.0 chip ID: 80ee:beef 
  Display: x11 server: X.Org 1.19.6 driver: modesetting unloaded: fbdev,vesa 
  alternate: vboxvideo resolution: 1920x1120~60Hz 
  OpenGL: renderer: Chromium v: 2.1 Chromium 1.9 direct render: Yes 

Additional context - my themes Borders: Mint-Y Dark (well, actually, I am using a customised version of that theme, but the problem occurs with the standard Mint-Y Dark too - and the Software Sources window does not honour my custom theme - but perhaps that is a problem with my theme). Icons: Mint-X Dark Controls: Mint-Y Dark Desktop: Mint-Y Dark

[gm10]

Agreed. Submitted the patch referenced above.