Comment 3 for bug 1354339

> jazzynico wrote:
> Changing the default units of a document should not affect it at all, it's just a different way of thinking about it.

Personally I do not completely agree, at least in the very specific case where I expect dimensions of the drawing to be stored in the specified document unit.
If only, a distinction should be made between the unit displayed in the toolboxes and in input fields, that when changed should not have any impact in the document but only "change the way of thinking it"; and the unit used to store coordinates of objects, that should be deeply tied to the document, preferably determined at the beginning of the work because when changed triggers a recalculation of all internally stored numbers to reflect the new preference.

I wouldn't mind having a pop-up saying that the whole document will be recalculated and asking for confirmation as the operation could be not so easily undoable.
In my mind, changing the document unit is like changing font in a wordprocessor textual document: what is written is unchanged but some aspects of the layout will probably need to be fixed: you usually think before doing it and expect some consequences (but in this case, it's easily undoable).

Of course, it's absolutely out of the question that the changes should be minimal: the program must do the best it can to convert from one unit to another with the highest available precision.
The posted example shows a clear bug: this is not expected to happen in any case.

I have to admit that the direction Inskcape is taking with regards to how to address this problem is unclear to me. There are still too many little bugs related to units handling that make me think it's being underestimate and set aside, somewhat.