Actions can be executed without frame containers again

Fixes issue 4160

Change-Id: If6b8a22932151e69d00fc588f16c2e9eadc65572
Reviewed-on: http://gerrit.dmdirc.com/1256
Reviewed-by: Gregory Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>

src/com/dmdirc/actions/ActionModel.java

@@ -147,7 +147,7 @@ public class ActionModel {
 
         if (arguments.length > 0 && arguments[0] instanceof Window) {
             window = (Window) arguments[0];
-        } else {
+        } else if (cw != null) {
             window = cw.getFrame();
         }