Index: pub/System/TinyMCEPlugin/foswiki_tiny_src.js
===================================================================
--- pub/System/TinyMCEPlugin/foswiki_tiny_src.js	(revision 8812)
+++ pub/System/TinyMCEPlugin/foswiki_tiny_src.js	(working copy)
@@ -89,6 +89,20 @@
 
     initialisedFromServer: false,
 
+	removeErasedSpans: function(ed, o) {
+		// forced_root_block makes TMCE insert   into empty spans.
+		// TML2HTML emits spans with the TMLwhitespace class
+		// that contain a single space.
+		// Some browsers (e.g. IE8 and Opera 10.60) remove the span if
+		// the user deletes the space within the span.
+		// Other browsers (e.g. various versions of Firefox) do not.
+		//
+		// This function removes spans with this class that contain
+		// only a   as the   is assumed to come from the
+		// forced_root_block code.
+		o.content = o.content.replace(/<span[^>]*class=['"][^'">]*TMLwhitespace[^>]+>&nbsp;<\/span>/g, '');
+	},
+
     // Set up content for the initial edit
     setUpContent: function(editor_id, body, doc) {
         // If we haven't done it before, then transform from TML
@@ -97,6 +111,9 @@
         if (FoswikiTiny.initialisedFromServer) return;
         var editor = tinyMCE.getInstanceById(editor_id);
         FoswikiTiny.switchToWYSIWYG(editor);
+
+		// Also add the handler for cleaning up after force_root_blocks
+		editor.onGetContent.add(FoswikiTiny.removeErasedSpans);
         FoswikiTiny.initialisedFromServer = true;
     },