Differentiating Fused from floating canvas.

[DoctorRN]

Hi, Can I ask some advice regarding differentiating fused and floating canvas. A couple of years ago I had a tailcoat made. I am just wondering whether it has a floating canvas. I have done the pinch test and there does appear to be a third layer underneath the bottom button, which is separate from the inside and outside layer. When I look at the buttonhole, there also appears to be a pale middle layer seen within the buttonhole which looks like canvassing (see picture).

My understanding is that fused canvassing tends to be black or dark grey in colour, whereas this is clearly pale (like most proper canvassing I have previously seen).

What do people think?

Many thanks.