fix for #64482. we enabled the download headers UI elements when we supposed to disable it, and vice version. sr=bienvenu

mailnews/news/resources/content/downloadheaders.js

@@ -103,16 +103,16 @@ function CancelButtonCallback() {
 	return true;
 }
 
-function doCheckboxEnabling() {
-  var allRadio = document.getElementById("all");
+function setupDownloadUI(enable) {
   var checkbox = document.getElementById("markread");
   var numberFld = document.getElementById("number");
-  if (allRadio && allRadio.checked) {
-    checkbox.setAttribute("disabled", "true");
-    numberFld.setAttribute("disabled", "true");
-  }
-  else {
+
+  if (enable) {
     checkbox.removeAttribute("disabled");
     numberFld.removeAttribute("disabled");
   }
+  else {
+    checkbox.setAttribute("disabled", "true");
+    numberFld.setAttribute("disabled", "true");
+  }
 }

mailnews/news/resources/content/downloadheaders.xul

@@ -44,10 +44,10 @@ Contributor(s):
   <separator class="thin"/>
   <box class="indent" orient="vertical">
     <radiogroup orient="vertical" id="downloadGroup" autostretch="never">
-      <radio group="downloadGroup" id="all" value="&all.label;" oncommand="doCheckboxEnabling(this);"/> 
+      <radio group="downloadGroup" id="all" value="&all.label;" oncommand="setupDownloadUI(false);"/> 
       <separator class="thin"/>
       <box autostretch="never" valign="middle">
-        <radio group="downloadGroup" id="some" checked="true" value="&download.label;" oncommand="doCheckboxEnabling(this);"/>
+        <radio group="downloadGroup" id="some" checked="true" value="&download.label;" oncommand="setupDownloadUI(true);"/>
         <textfield id="number" size="7"/>
         <text class="label" value="&headers.label;" />
       </box>