Allow alignment of mixed dimensionality layers about affinder

[thanushipeiris]

@jni Could you please provide a bit more explanation about how these two use cases differ? I am unfamiliar with them.

I think I understand what you mean by

treat the 2D image as a very thin 3D slice

That's like if you did a low res scan of a 3D volume and a high res imaging of an ROI in 2D then wanted to position your
ROI within the larger volume. But I don't get

treat it as "limited" to the two right-aligned dimensions

Is the neuron segmentation in 2D while the calcium imaging timeseries in 2D + t? So you'd just want to copy the same neuron segmentation over time?

[jni]

Yep, both your interpretations are correct. The segmentation applies equally to every time point. One specific example that triggered this issue was aligning an island's contour coordinates (a shapes layer) with a time-series of surface temperature on the island.