src/extensions/default/NavigationAndHistory/NavigationProvider.js
function _backupLiveMarkers(frames, editor) {
        var index, frame;
        for (index in frames) {
            frame = frames[index];
            if (frame.cm === editor._codeMirror) {
                frame._handleEditorDestroy();
            }
        }
    }
function _backupLiveMarkers(frames, editor) {
        var index, frame;
        for (index in frames) {
            frame = frames[index];
            if (frame.cm === editor._codeMirror) {
                frame._handleEditorDestroy();
            }
        }
    }
function _backupLiveMarkers ( frames , editor ) { var index , frame ; for ( index in frames ) { frame = frames [ index ] ; if ( frame . cm === editor . _codeMirror ) { frame . _handleEditorDestroy ( ) ; } } }
Create snapshot of last known live markers.
@private
Create snapshot of last known live markers .