b4af2f7fbaae0ef4561a937bbc768b2f362f7cd9
angie
  Thu Feb 27 10:59:42 2014 -0800
Fixing a couple bugs uncovered by MLQ #12777: first, the intersectionbutton was appearing even for tables that don't pass canIntersect().
Second, canIntersect() was returning false for VCF instead of true.
So the intersect button appeared for VCF tracks, but the user's
intersection settings were ignored.  Now intersection works for VCF.
refs #12777

diff --git src/hg/hgTables/mainPage.c src/hg/hgTables/mainPage.c
index 4fee520..d576dbb 100644
--- src/hg/hgTables/mainPage.c
+++ src/hg/hgTables/mainPage.c
@@ -782,31 +782,31 @@
 	}
     hPrintf("</TD></TR>\n");
     }
 
 /* Intersection line. */
 if (isPositional)
     {
     if (anyIntersection())
         {
 	hPrintf("<TR><TD><B>intersection with %s:</B>\n",
 		cartString(cart, hgtaIntersectTable));
 	cgiMakeButton(hgtaDoIntersectPage, "edit");
 	hPrintf(" ");
 	cgiMakeButton(hgtaDoClearIntersect, "clear");
 	}
-    else
+    else if (canIntersect(database, curTable))
         {
 	hPrintf("<TR><TD><B>intersection:</B>\n");
 	cgiMakeButton(hgtaDoIntersectPage, "create");
 	}
     hPrintf("</TD></TR>\n");
     }
 
 /* Correlation line. */
 struct trackDb *tdb = findTdbForTable(database, curTrack, curTable, ctLookupName);
 if (correlateTrackTableOK(tdb, curTable))
     {
     char *table2 = cartUsualString(cart, hgtaCorrelateTable, "none");
     hPrintf("<TR><TD><B>correlation:</B>\n");
     if (differentWord(table2,"none") && strlen(table2))
         {