Bug: Dead layer

While I was working on a multi-layer fractal, one of the layers stopped working. Zooming and panning don't trigger a re-draw.

I removed the other layers, reset the location to default, removed transform, reset fractal, inside and outside all to default, saved, closed and re-opened UF6, loaded, and it's still dead.

Have a look.

https://drive.google.com/file/d/1ZzzPToBLIJ1iM0JV3nmrH9-aBR_L9z9L#dead-layer.ufr

The Coloring tab is set to None. If I change that, I get an image.

I did what you describe but I still don't get an image. Tried changing "Inside" and "Outside" and several standard and custom formulas.

I loaded dead-layer.ufr into UF. When I clicked on the Browse button to the right of (None) on the Outside tab, various images showed in the preview pane. But when I changed the coloring to Mandelbrot from Standard.ucl, the image was still blank.

I saved it to a upr file and reloaded it in UF and got an appropriate image. Definitely strange. I always save as upr files and have never used ufr files, so maybe there's something strange about them.

Here's the upr:
/>dead-layer {
fractal:
title="dead-layer" width=2304 height=1728 layers=1 frames=144 fps=1
credits="Mark Jeronimus;6/4/2026"
layer:
caption="Layer 2" opacity=100 mergemode=darken
mapping:
center=-0.5/0 magn=1
formula:
maxiter=100000 perturbprecision=veryfast filename="Standard.ufm"
entry="Mandelbrot" p_start=0/0 p_power=2/0 p_bailout=1e10
inside:
transfer=none
outside:
transfer=linear
gradient:
smooth=no rotation=1 index=0 color=0 index=399 color=16777215
opacity:
smooth=no index=0 opacity=255
}