public void setResizable(boolean resizable) {
        putBoolean("Resizable", resizable);
    }
Allows the display window to be resized by dragging its edges.

Only supported for {@link JmeContext.Type#Display} contexts which
are in windowed mode, ignored for other types.
The default value is <code>false</code>.

@param resizable True to make a resizable window, false to make a fixed
size window.
jme3-core/src/main/java/com/jme3/system/AppSettings.java