Comment 2 for bug 787568

Please provide information about your OS/platform and Inkscape version and attach the sample SVG file used for the screenshot. with a list of 'steps to reproduced'.

Note that Inkscape 0.48 uses a more precise calculation method for export to bitmap as well as when resizing the page to selection, but not for rendering the selection bounding box on-canvas because the calculation is expensive and would slowly down interactive usage far too much (as currently happens when keeping the export dialog opened, as reported in bug #719993).

See also <http://thread.gmane.org/gmane.comp.graphics.inkscape.devel/33883/focus=33886>

Related reports (fixed in 0.48):
Bug #166659 “Bounding box does not include long miters”
Bug #479964 “"Fit Page to Selection" doesn't take arrow heads into account”