CSSProperty: fixed cast exception in toString()
diff --git a/compiler/src/main/java/org/apache/royale/compiler/internal/css/CSSProperty.java b/compiler/src/main/java/org/apache/royale/compiler/internal/css/CSSProperty.java
index 9b3ddf1..0f4c0a2 100644
--- a/compiler/src/main/java/org/apache/royale/compiler/internal/css/CSSProperty.java
+++ b/compiler/src/main/java/org/apache/royale/compiler/internal/css/CSSProperty.java
@@ -57,7 +57,7 @@
     @Override
     public String toString()
     {
-        if (rawName.equalsIgnoreCase("border"))
+        if (rawName.equalsIgnoreCase("border") && value instanceof CSSArrayPropertyValue)
         {
             CSSArrayPropertyValue borderValues = (CSSArrayPropertyValue)value;
             return String.format("%s: %s;", rawName, Joiner.on(" ").join(borderValues.getElements()));