Fix for selecting columns and floating table header

Turn off floating table header on popup showing, turn it on (if it was
off) again when it is closed.
This has a negative side-effect of header disappearing behind the
content pane popup, but that is barely noticeable.

benchexec/tablegenerator/template.html

@@ -322,6 +322,12 @@
     $('#contentPaneBackground').hide();
     $('#contentPane').hide().empty();
   }
+
+  // On closing the dialog, turn on the scrollable header, if it's not on
+  // already.
+  if ($('#floatThead-container').size() == 0) {
+      useFloatThead();
+  }
 }
 
 function escKeyPressed(event) {
@@ -351,15 +357,19 @@
        + (runSet.benchmarkname ? '.' + runSet.benchmarkname : '');
 }
 
-$(document).ready(function() {
-  $('body').keydown(hideContentPane);
+function useFloatThead() {
   $("#dataTable").floatThead({
 
     // Offset after the floating header.
     scrollingTop:$("#header").outerHeight(true),
     useAbsolutePositioning:false,
     zIndex:3
   });
+}
+
+$(document).ready(function() {
+  $('body').keydown(hideContentPane);
+  useFloatThead();
 });
 
 </script>
@@ -530,6 +540,8 @@
 
 
 function createColumnToggleView() {
+    // Turn the float-thead on and off.
+    $("#dataTable").floatThead('destroy');
 
     // collect all columns
     var columnTitles = [];