Bug 1860218 - Fix composer's Color properties dialog. r=aleca

Differential Revision: https://phabricator.services.mozilla.com/D191510

--HG--
extra : amend_source : 06bcc2812017e1563597d55033d01c3491a78792

mail/components/compose/content/dialogs/EdColorProps.xhtml

@@ -141,7 +141,7 @@
             </button>
           </vbox>
         </hbox>
-        <vbox id="ColorPreview" flex="1">
+        <vbox id="ColorPreview">
           <spacer flex="1" />
           <label class="larger" id="NormalText" value="&normalText.label;" />
           <spacer flex="1" />

mail/themes/shared/mail/EditorDialog.css

@@ -62,7 +62,7 @@
   width: 30px;
   height: 12px;
   border: 1px inset #CCCCCC;
-  margin: 1px 0;
+  margin: auto;
 }
 
 .color-well[default="true"] {