I'm having the same issue with a custom panel ui.
I've had success with technical support on this forum in the past, so I'd imagine the more information we can provide to help target the problem, the faster we'll get the help we need.
To that end...
Sencha Cmd v184.108.40.2068
My app.scss has the ui built as:
I get the styling I expect for FF v20.0.1 (I assume it's using CSS3), however for IE9, I'm seeing some changes, but the header panel background isn't right in collapsed mode.
$ui-header-background-gradient: gradient(#3668AF, #3668AF)
I'm seeing requests for 2 files that "compass" apparently hasn't generated:
Where "Demo" is the project name, and "ptv" is the theme name.