A DESCRIPTION OF THE PROBLEM :
I've set the following CSS class to change the ChoiceBox and TextField context-menu, especially its background shadow, it works perfectly on Windows platform but on one of the Debian based Linux distros (Crunchbang++) it doesn't work as expected, Actually when I set -fx-effect to the null value there will be another default shadow (secondary) behind the context-menu (exactly like the shadow around the main window of the application) and there is no way to disable it, same will happen to tooltips!

.context-menu {
    -fx-background-color: #fff;
    -fx-background-radius: 2;
    -fx-padding: 0.6em 0 0.6em 0;
    -fx-text-fill: #444;
    -fx-effect: null;
}

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Put three different controls on the scene, a ChoiceBox, a TextField and a Button that contains a Tooltip, then in your CSS file that is attached to the scene, define the following rule to remove the default ContextMenu background shadow:

.context-menu {
    -fx-effect: null;
}

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Remove the shadow behind and around the ContextMenu and Tooltip! (When opening a ChoiceBox list, showing a tooltip and doing a right-click on a TextField)
ACTUAL -
There will be a shadow that resembles the one around the main window of the application.