Fixes for nullable selection (VE-MW)

gistfile1.diff

diff --git a/modules/ve-mw/init/targets/ve.init.mw.ViewPageTarget.js b/modules/ve-mw/init/targets/ve.init.mw.ViewPageTarget.js
index 40cd5c4..cfe5584 100644
--- a/modules/ve-mw/init/targets/ve.init.mw.ViewPageTarget.js
+++ b/modules/ve-mw/init/targets/ve.init.mw.ViewPageTarget.js
@@ -715,11 +715,14 @@ ve.init.mw.ViewPageTarget.prototype.onToolbarMetaButtonClick = function () {
  * @param {ve.dm.Transaction} transaction
  */
 ve.init.mw.ViewPageTarget.prototype.checkForWikitextWarning = function () {
-       var text, doc = this.surface.getView().getDocument(),
+       var text, node, doc = this.surface.getView().getDocument(),
                selection = this.surface.getModel().getSelection(),
-               node = doc.getNodeFromOffset( selection.start ),
                textMatches,
                viewPageTarget = this;
+       if ( !selection ) {
+               return;
+       }
+       node = doc.getNodeFromOffset( selection.start );
        if ( !( node instanceof ve.ce.ContentBranchNode ) ) {
                return;
        }