Accessing grid object from status bar button

Hi!

I have a question:
I have a “classical” layout window with a grid attached to one of the cells.
Now i would like to attach a status bar to the cell and include undo/redo buttons linked to the grid.

var main_layout = wdwMain.attachLayout('3T');
var a = main_layout.cells('a');
var overviewStatus = a.attachStatusBar();
overviewStatus.setText("<div><input id='z1' type='button' onclick='overviewGrid.doUndo();' value='Undo'><input id='z1' type='button' onclick='overviewGrid.doRedo();' value='Redo'></div>");
var overviewGrid = a.attachGrid();
...

However the buttons trigger the message Uncaught ReferenceError: overviewGrid is not defined .

I guess the grid is out of scope, how can i solve this?
Many thanks
Pavol

Unfortunately the issue cannot be reconstructed locally.
If issue still occurs - please, provide a more complete sample of your code, demo link where the issue can be reconstructed or a complete demo.