Comment 15 for bug 168320

I have encountered this same problem in the most recent Windows binary (0.45+0.46pre0). After manually changing the default font in preferences.xml (since "Bitstream Vera Sans" was actually "Bitstream Vera Sans Mono" on my system) I was then able to change fonts through the toolbar only after first applying a font change through the text properties dialog. This caused me to look into the XML Editor to compare and found that within the text element's style attribute the following was missing by default: -inkscape-font-specification. After updating the element through the text dialog this tag was populated. I assume then that inkscape is missing a default directive to change the font if this tag is not present in the style directive (manually removing the tag from a complete style attribute also failed to allow for toolbar font changes and seems to confirm this theory)...