Some lines are hard to click

When I edit a sketch of a part directly in a assembly, somes lines from another part are hard to select (im triing to offset thems).  The faces are super easy but the ''box of selection'' for the edges is just too small.  I can select thems but it take me 2-3 try and must zoom in very close.  I was not having this problem when using 2015 version. Sorry for bad grammar im not english native.

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