Undo in WikkaEdit sometimes selects the whole textarea

[OlivierBorowski]

Summary

When Javascript does some change in textarea content, undo (Ctrl+Z) select the whole textarea instead of the previous selected content.

Testcase

- type "test" in the textarea
- remove "test" for example with the "delete" key => after that, undo works
- select "test" and click on "bold" (Ctrl+B) => then, undo will select everything