10.1 Predictable disadvantage; non-functional modification; arbitrary choice 

If an invention is the result of a foreseeable disadvantageous modification of the closest prior art which the skilled person could clearly predict and correctly assess, and if this predictable disadvantage is not accompanied by an unexpected technical advantage, then the claimed invention does not involve an inventive step (see T 119/82 and T 155/85). In other words, a foreseeable worsening of the prior art does not on its own involve an inventive step but it may involve one if it is accompanied by an unexpected technical advantage. Similar considerations apply where an invention is merely the result of an arbitrary non-functional modification of a prior-art device or of a merely arbitrary choice from a host of possible solutions (see T 72/95 and T 939/92).