Failing to locate the content document for RSS documents, dereferencing null

[eyalroz]

In some cases - specifically, when reading RSS-obtained documents sometimes, I can't cycle directions:

  cycleDirectionSettings : function() {
    var messagePane = document.getElementById("messagepane");
    var body = messagePane.contentDocument.body;
    var newForcedDirection;
    switch (body.getAttribute('bidimailui-forced-direction')) {
      case 'ltr':
        newForcedDirection = 'rtl';
        break;
      case 'rtl':
        newForcedDirection = null;
        break;
      default: // should be null
        newForcedDirection = 'ltr';
    }

messagepane is not null, but the contentDocument is missing/null. So, we fail to get the body.

[eyalroz]

Also getting a failure in:

  gatherParameters : function() {
    if (!msgWindow) { return [null, null, null]; }
    let domDocument =  msgWindow.messageWindowDocShell.contentViewer.DOMDocument;

sometimes.

[eyalroz]

This should be resolved by the commits fixing bug #97 for TB 115 and later.