Undo not working when we change the Table Properties for the table on a saved page

[Satya Minnekanti]

To reproduce the defect

1. Open Ajax sample.

2. Insert a Table and enter the text in Table Cells.

3. Click on Remove Editor button to save the Page.

4. Click on Create Editor button to open the page again.

5. Go in to one of Table cells and Open Table Context menu and Click on Table Properties.

6. In Table Properties dialog change Table Alignment to Center and Click OK.

Expected Result

Table is Aligned to Center and the Undo button should be enabled.

Actual Result

Table is Aligned to the Center but the Undo button is not enabled and it will not enable even if we change any number of Table Properties.It is only enabled when we type some text in the Editor.

[Garry Yao]

We have similar issues in other dialogs, e.g. insert Link, it's not bad to take a bit automation here.

[Tobiasz Cudnik]

This is a good solution which resolves other issues like #5846.

We may additionally remove some savesnapshot events in other dialogs, which will be unnecessary after this fix.

[Tobiasz Cudnik]

Fixed with [5669].

[Tobiasz Cudnik]

Committed into correct branch with [5693].