Issue 3955 - Set required ABP version properly when exporting filter lists with CSS property filters

chrome/content/ui/filters-backup.js

Index: chrome/content/ui/filters-backup.js
===================================================================
--- a/chrome/content/ui/filters-backup.js
+++ b/chrome/content/ui/filters-backup.js
@@ -310,17 +310,20 @@ var Backup =
         if (filter instanceof CommentFilter && this.GROUPTITLE_REGEXP.test(filter.text))
           continue;
         list.push(filter.text);
 
         if (filter instanceof ElemHideException && Services.vc.compare(minVersion, "2.1") < 0)
           minVersion = "2.1";
 
         if (filter instanceof RegExpFilter && filter.contentType & (RegExpFilter.typeMap.GENERICHIDE | RegExpFilter.typeMap.GENERICBLOCK) && Services.vc.compare(minVersion, "2.6.12") < 0)
-          minVersion  = "2.6.12";
+          minVersion = "2.6.12";
+
+        if (filter instanceof CSSPropertyFilter && Services.vc.compare(minVersion, "2.7.3") < 0)
+          minVersion = "2.7.3";
       }
     }
     list.unshift("[Adblock Plus " + minVersion + "]");
 
     // Insert checksum. Have to add an empty line to the end of the list to
     // account for the trailing newline in the file.
     list.push("");
     let checksum = Utils.generateChecksum(list);