JAL-147 prevent overview box move up over hidden first sequence

[jalview.git] / src / jalview / viewmodel / OverviewDimensionsShowHidden.java

diff --git a/src/jalview/viewmodel/OverviewDimensionsShowHidden.java b/src/jalview/viewmodel/OverviewDimensionsShowHidden.java
index 4b396a6..2216f33 100644 (file)
--- a/src/jalview/viewmodel/OverviewDimensionsShowHidden.java
+++ b/src/jalview/viewmodel/OverviewDimensionsShowHidden.java
@@ -135,10 +135,12 @@ public class OverviewDimensionsShowHidden extends OverviewDimensions
     // so convert back after getting visible region position
     yAsSeq = hiddenSeqs.adjustForHiddenSeqs(hiddenSeqs
             .findIndexWithoutHiddenSeqs(yAsSeq));
+    yAsSeq = Math.max(yAsSeq, 0); // -1 if before first visible sequence
 
     // check in case we went off the edge of the alignment
     int visAlignHeight = hiddenSeqs.findIndexWithoutHiddenSeqs(alheight);
     int visYAsSeq = hiddenSeqs.findIndexWithoutHiddenSeqs(yAsSeq);
+    visYAsSeq = Math.max(visYAsSeq, 0); // -1 if before first visible sequence
     if (visYAsSeq + vpheight - 1 > visAlignHeight)
     {
       // went past the end of the alignment, adjust backwards
@@ -156,7 +158,6 @@ public class OverviewDimensionsShowHidden extends OverviewDimensions
     // update viewport
     ranges.setStartRes(visXAsRes);
     ranges.setStartSeq(visYAsSeq);
-
   }
 
   /**