If its null, set tip empty

diff --git a/src/jalview/appletgui/Tooltip.java b/src/jalview/appletgui/Tooltip.java
index 76c0047..9306e3d 100755 (executable)
--- a/src/jalview/appletgui/Tooltip.java
+++ b/src/jalview/appletgui/Tooltip.java
@@ -102,6 +102,11 @@ public class Tooltip extends Canvas implements MouseListener,
 \r
         void setTip(String tip)\r
         {\r
+          if(tip==null)\r
+          {\r
+            setTip("");\r
+            return;\r
+          }\r
           fm = getFontMetrics(owner.getFont());\r
           fontHeight = fm.getHeight();\r
 \r