Disable the selected text on a multi-line field upon focus

Whenever I enter a multi-line text field, the whole text is selected and pressing any key to edit (other than a cursor key, or home) will delete the whole content of the multiline.
I am using a quick fix to that with the following javascript code:

document.selection.empty();

I add that to each multi-line input control (on the Javascript section of the form settings, on the onfocus event) and that way the problem is solved.

It would be nice if this was added as a default option for multi-line fields, maybe on a check box to let the developer decide if they want to have the whole text selected upon focus, or if they do not want it that way.
Someone from my team told me she was wasting a lot of time when doing data entry because she would deleted by mistake the whole text almost every time she focused on that specific field.

Then please tell them also to use ctrl-Z to restore if they did that.