Fixing bug 1244, manually entered tax crashes edit screen

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extra : source : 67d99042c4ac564ef14a6ced321397859a470d84
Updated changelog

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extra : source : 00b740773050afb1bdb8f4417a572e8b126666bc
Merge pull request #448 from einhverfr/master

Fixing bug 1244, manually entered tax crashes edit screen