message: Fix close button size issue (mac),
diff: <rect key="frame" x="315" y="475" width="20" height="25"/>
  <constraints>
  <constraint firstAttribute="width" constant="20" id="O7b-Hm-mwT"/>
  + <constraint firstAttribute="height" constant="25" id="obC-fA-Eo8"/>
  </constraints>
  <buttonCell key="cell" type="roundTextured" bezelStyle="texturedRounded" image="NSStopProgressTemplate" imagePosition="only" alignment="center" refusesFirstResponder="YES" imageScaling="proportionallyDown" inset="2" id="LqD-Ld-bLi">
  <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
  <constraint firstAttribute="trailing" secondItem="fz4-yg-eQZ" secondAttribute="trailing" constant="10" id="3gJ-jS-6en"/>
  <constraint firstItem="ByL-Em-l61" firstAttribute="top" secondItem="Uof-FM-Nqj" secondAttribute="bottom" constant="10" id="3rT-hy-ihj"/>
  <constraint firstItem="cv5-TQ-M7L" firstAttribute="leading" secondItem="gq5-PC-ftr" secondAttribute="leading" constant="15" id="7KZ-bG-3Lk"/>
  - <constraint firstItem="zwE-pW-vQN" firstAttribute="top" secondItem="gq5-PC-ftr" secondAttribute="top" constant="6" id="E6a-vh-XAz"/>
  + <constraint firstItem="zwE-pW-vQN" firstAttribute="top" secondItem="gq5-PC-ftr" secondAttribute="top" constant="2" id="E6a-vh-XAz"/>
  <constraint firstItem="cv5-TQ-M7L" firstAttribute="top" secondItem="gq5-PC-ftr" secondAttribute="top" constant="25" id="EFB-l3-BIT"/>
  <constraint firstAttribute="trailing" secondItem="cv5-TQ-M7L" secondAttribute="trailing" constant="15" id="FcF-DW-3UI"/>
  <constraint firstAttribute="trailing" secondItem="ByL-Em-l61" secondAttribute="trailing" id="PCc-pA-fB1"/>
  