XWIKI-13967: Confusion between Supported Languages and Default Languages when...

XWIKI-13967: Confusion between Supported Languages and Default Languages when multilingual is set to no (#2770)

* Added a CSS ruleset to remove the supported languages field from the UI when it's not useful.

xwiki-platform-core/xwiki-platform-administration/xwiki-platform-administration-ui/src/main/resources/XWiki/AdminLocalizationSheet.xml

@@ -441,4 +441,130 @@
       <use>currentPage</use>
     </property>
   </object>
+  <object>
+    <name>XWiki.AdminLocalizationSheet</name>
+    <number>0</number>
+    <className>XWiki.StyleSheetExtension</className>
+    <guid>3af35852-ce5c-402a-8a09-16ee04654aac</guid>
+    <class>
+      <name>XWiki.StyleSheetExtension</name>
+      <customClass/>
+      <customMapping/>
+      <defaultViewSheet/>
+      <defaultEditSheet/>
+      <defaultWeb/>
+      <nameField/>
+      <validationScript/>
+      <cache>
+        <cache>0</cache>
+        <defaultValue>long</defaultValue>
+        <disabled>0</disabled>
+        <displayType>select</displayType>
+        <freeText>forbidden</freeText>
+        <largeStorage>0</largeStorage>
+        <multiSelect>0</multiSelect>
+        <name>cache</name>
+        <number>5</number>
+        <prettyName>Caching policy</prettyName>
+        <relationalStorage>0</relationalStorage>
+        <separator> </separator>
+        <separators>|, </separators>
+        <size>1</size>
+        <unmodifiable>0</unmodifiable>
+        <values>long|short|default|forbid</values>
+        <classType>com.xpn.xwiki.objects.classes.StaticListClass</classType>
+      </cache>
+      <code>
+        <contenttype>PureText</contenttype>
+        <disabled>0</disabled>
+        <editor>PureText</editor>
+        <name>code</name>
+        <number>2</number>
+        <prettyName>Code</prettyName>
+        <restricted>0</restricted>
+        <rows>20</rows>
+        <size>50</size>
+        <unmodifiable>0</unmodifiable>
+        <classType>com.xpn.xwiki.objects.classes.TextAreaClass</classType>
+      </code>
+      <contentType>
+        <cache>0</cache>
+        <disabled>0</disabled>
+        <displayType>select</displayType>
+        <freeText>forbidden</freeText>
+        <largeStorage>0</largeStorage>
+        <multiSelect>0</multiSelect>
+        <name>contentType</name>
+        <number>6</number>
+        <prettyName>Content Type</prettyName>
+        <relationalStorage>0</relationalStorage>
+        <separator> </separator>
+        <separators>|, </separators>
+        <size>1</size>
+        <unmodifiable>0</unmodifiable>
+        <values>CSS|LESS</values>
+        <classType>com.xpn.xwiki.objects.classes.StaticListClass</classType>
+      </contentType>
+      <name>
+        <disabled>0</disabled>
+        <name>name</name>
+        <number>1</number>
+        <prettyName>Name</prettyName>
+        <size>30</size>
+        <unmodifiable>0</unmodifiable>
+        <classType>com.xpn.xwiki.objects.classes.StringClass</classType>
+      </name>
+      <parse>
+        <disabled>0</disabled>
+        <displayFormType>select</displayFormType>
+        <displayType>yesno</displayType>
+        <name>parse</name>
+        <number>4</number>
+        <prettyName>Parse content</prettyName>
+        <unmodifiable>0</unmodifiable>
+        <classType>com.xpn.xwiki.objects.classes.BooleanClass</classType>
+      </parse>
+      <use>
+        <cache>0</cache>
+        <disabled>0</disabled>
+        <displayType>select</displayType>
+        <freeText>forbidden</freeText>
+        <largeStorage>0</largeStorage>
+        <multiSelect>0</multiSelect>
+        <name>use</name>
+        <number>3</number>
+        <prettyName>Use this extension</prettyName>
+        <relationalStorage>0</relationalStorage>
+        <separator> </separator>
+        <separators>|, </separators>
+        <size>1</size>
+        <unmodifiable>0</unmodifiable>
+        <values>currentPage|onDemand|always</values>
+        <classType>com.xpn.xwiki.objects.classes.StaticListClass</classType>
+      </use>
+    </class>
+    <property>
+      <cache>long</cache>
+    </property>
+    <property>
+      <code>/* Do not display the supported language field (we assume it's the following one)
+  when the multilingual option is set to No. */
+form#localization dd:has(> div.dropdown > select[name="XWiki.XWikiPreferences_0_multilingual"] > option[value="0"]:checked) + dt,
+form#localization dd:has(> div.dropdown > select[name="XWiki.XWikiPreferences_0_multilingual"] > option[value="0"]:checked) + dt + dd {
+  display: none;
+}</code>
+    </property>
+    <property>
+      <contentType/>
+    </property>
+    <property>
+      <name/>
+    </property>
+    <property>
+      <parse/>
+    </property>
+    <property>
+      <use>currentPage</use>
+    </property>
+  </object>
 </xwikidoc>