Combobox readonly problem

I have a combox in one form , this combo is readOnly.
When i click the disabled combo box i see the blue border.
My theme is runo.
I saw that apply the class v-filterselect-focus … If i select a text field the are not this behavior.
I don’t know how remove this border when is disable the combo.
if i change the css i loose this behavior when is enable the combo…
Someone know how remove that border?
Thak’s marco

Ops… the source

public void init() {
Window mainWindow = new Window("TestCombo");
    this.setTheme("runo");
    ComboBox cmb = new ComboBox("Combo");
    cmb.addItem("");
    cmb.addItem("Select 1");
    cmb.addItem("Select 2");
    cmb.setReadOnly(true);


mainWindow.addComponent(cmb);
setMainWindow(mainWindow);
}

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