Can anyone explain why this display distortion happens when entering multiple arguments?

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This is an If / Or formula and this distortion happens after the third value ...
I start with the IF formula. Then at the "logical_test" field I insert the OR function.
Then inserting a value at the Logical1, Logical2, Logical3 ... the distortion appears...
Excel 2010 ver. 14.0.7147.5001 (32-bit) / Windows 7 Home Premium 64bit