You should first create your own 9-patch image with the colours which you want to use. For example an image like this :
And after that in your application's theme you should add this (for Holo Theme) :
<style name="Theme.MyAppTheme" parent="@android:style/Theme.Holo.Light">
<item name="android:actionModeBackground">@drawable/my_actionmode_background</item>
</style>
For ActionBarSherlock
or AppCompat
you should use :
<!-- AppCompat -->
<style name="Theme.MyAppTheme" parent="@style/Theme.AppCompat.Light">
<item name="actionModeBackground">@drawable/my_actionmode_background</item>
</style>
<!-- ActionBarSherlock -->
<style name="Theme.MyAppTheme" parent="@style/Theme.Sherlock.Light">
<item name="actionModeBackground">@drawable/my_actionmode_background</item>
</style>