set special style for a combobox

Hello,

we have found a strange css problem with a combobox:

 IndexedContainer c = new IndexedContainer();
c.addItem("Alpha");
c.addItem("Beta");
c.addItem("Gamma");
c.addItem("Delta");
ComboBox box = new ComboBox("Combo", c);

Page.getCurrent().getStyles().add(".v-app .v-filterselect-suggestpopup.fdsa [class$=\"suggestmenu\"] {background-color: #17ffff; color: #ff17ff; text-shadow:2px 2px 0px yellow; font-family:Segoe UI; font-style: italic; font-weight: bold;}");
Page.getCurrent().getStyles().add(".v-app .v-filterselect.asdf [class$=\"input\"] {background-color: #17ffff; color: #ff17ff; text-shadow:2px 2px 0px yellow; font-family:Segoe UI; font-style: italic; font-weight: bold;}");

box.setStyleName("fdsa");
box.setStyleName("asdf");

The goal is to set Color and font and so  on for the whole Combobox.
When we set only the special style 'asdf' it is working. Then the input part of the combobox has a style as described.
But, when we try to set 'fdsa' it seems to be ignored.

Can anybody tell me why?

Thanks

Christoph