Comment 17 for bug 1239682

well in that case we do indeed have a problem. There are a number of reasons why it would create a problem if rev 13938 were reverted. First of all, it is a duplicate of rev 12575 which solved a number of bugs associated with importing files which originated from other software, not Inkscape. Rev 12575 unfortunately modified only the file_new routine and neglected to modify the file_open routine. Rev 13938 corrects that oversight. The point is that you cannot allow different behavior between a file open command and a file new command. This would mean that someone could create a template file using file_open and then try to use it as a template, which uses file_new, and they would discover that it no longer worked.
 There are two cases that I have seen so far where there is a potential problem. The first case is the one mentioned above where you have an Inkscape file created with Inscape 0.48 or earlier and where the document-units are not px. I am attaching an example here, ellipse_48_mm.svg. If you load this in rev13938 or newer, the ellipse in it will be too large. The reason it is too large is because the original Inkscape program stored the data in units of px despite the fact that the document-units were called mm. This was an error caused by an incomplete implementation of the concept of document units, not related to the viewbox in any way. The way to fix it is to edit the file and remove the line that says 'inkscape:document-units="mm"'. Then the file will load correctly. What we need is an automatic routine that the user could optionally use at their own discretion to do just that, similar to what we will need in order to resolve any discrepancies between 90 dpi and 96 dpi. The user needs to get involved at this point and make the decision as to whether to convert or not convert.