0a3231ebfd87922c3e0735eba832195d37dd36bf
kate
  Tue Aug 29 16:42:18 2017 -0700
A little seg-fault protection.

diff --git src/hg/hgTracks/gtexTracks.c src/hg/hgTracks/gtexTracks.c
index 1ddde66..6a0ac36 100644
--- src/hg/hgTracks/gtexTracks.c
+++ src/hg/hgTracks/gtexTracks.c
@@ -1104,31 +1104,31 @@
     heightPer = gtexSquishItemHeight() * 2;  // the squish packer halves this
     lineHeight=heightPer+1;
     }
 else if ((vis == tvPack) || (vis == tvFull))
     {
     // layout -- initially as fixed height
     heightPer = tl.fontHeight;
     lineHeight=heightPer;
     }
 
 height = tgFixedTotalHeightOptionalOverflow(tg, vis, lineHeight, heightPer, FALSE);
 
 if ((vis == tvPack) || (vis == tvFull))
     {
     // set variable height rows
-    if (tg->ss->rowCount != 0)
+    if (tg->ss && tg->ss->rowCount != 0)
         {
         if (!tg->ss->rowSizes)
 	    {
 	    // collect the rowSizes data across all windows
 	    assert(currentWindow==windows); // first window
 	    assert(tg->ss->vis == vis); // viz matches, we have the right one
 	    struct spaceSaver *ssHold; 
 	    AllocVar(ssHold);
 	    struct track *tgSave = tg;
 	    for(tg=tgSave; tg; tg=tg->nextWindow)
 		{
 		assert(tgSave->ss->vis == tg->ss->vis); // viz matches, we have the right one
 		spaceSaverSetRowHeights(tg->ss, ssHold, gtexGeneHeight);
 		}
 	    // share the rowSizes data across all windows