--context does not work correctly with --display=inline

[Andriamanitra]

Let's say you have files a and b with the following content:

Line 1
Line 2
Line 3
Line 4
Line 5
Line 6
Line 7

Line 1
Line 2
Line 3
Line X
Line 5
Line 6
Line 7

When diffing them with difft --context=1 --display=inline the output shows lines 1 to 6:

I would expect only lines 3, 4, and 5 to be visible regardless of which --display option you're using.