a57b88d0d1e45c647aa38cd739543f570c4133de
max
  Thu Nov 25 03:20:57 2021 -0800
adding mouseover text to folder icon, refs #28558

diff --git src/hg/lib/hui.c src/hg/lib/hui.c
index b8427fa..fd0051b 100644
--- src/hg/lib/hui.c
+++ src/hg/lib/hui.c
@@ -9453,33 +9453,36 @@
 slReverse(&list);
 return list;
 }
 
 void hPrintIcons(struct trackDb *tdb) 
 /* prints optional folder and pennants icons and a space, if any icons were printed */
 {
 bool hasIcon = hPrintPennantIcon(tdb);
 if (tdbIsSuper(tdb) || tdbIsComposite(tdb))
     {
     // this is the folder.svg icon from the font-awesome collection.
     // the icon collection also contains a "fa fa-folder-o" icon, which is the outlined version 
     // It was decided to use only the filled out icon for now and use the same icon for super
     // and composite tracks. Adding the SVG removes a dependency and makes the icons show up instantly,
     // instead of the short delay when using fonts. Github uses icons like this.
-    hPrintf("<svg class='folderIcon' viewBox='0 0 512 512'><path fill='#00457c' "
+    hPrintf("<span title='The folder icon indicates that this is a container track. "
+            "Even if the container track is not hidden itself, it may have subtracks that are hidden. "
+            "Click the track here or right-click on the image and configure to see all possible subtracks.'>"
+            "<svg class='folderIcon' viewBox='0 0 512 512'><path fill='#00457c' "
             "d='M464 128H272l-64-64H48C21.49 64 0 85.49 0 112v288c0 26.51 21.49 48 48 48h416c26.51 "
-            "0 48-21.49 48-48V176c0-26.51-21.49-48-48-48z'/></svg>");
+            "0 48-21.49 48-48V176c0-26.51-21.49-48-48-48z'/></svg></span>");
     hasIcon = TRUE;
     }
 if (hasIcon)
     hPrintf(" ");
 }
 
 boolean hPrintPennantIcon(struct trackDb *tdb)
 // Returns TRUE and prints out the "pennantIcon" when found.
 // Example: ENCODE tracks in hgTracks config list.
 {
 if (trackDbSetting(tdb, "wgEncode") != NULL)
     {
     hPrintf("<a title='encode project' href='../ENCODE'><img height='16' width='16' "
             "src='../images/encodeThumbnail.jpg'></a>\n");
     }