Very slow material editor response with "transform" involved

[Cinemike]

Create a Corona material, load a hires texture (i used 8kx8k) into diffuse and create a layer shader (the texture is now with the layer shader). It does not matter either whether you embed the texture in a Corona bitmap shader.
Add "Transform" from "Effect..." in the layer shader. It will already take a few seconds until it shows.
Try to change the "Scale" values of the "Transform" effect, you will get a very sluggish response. Adapting a material will be no fun.
Now select the texture and add a "Filter" shader. The bitmap will now be embedded in the filter shader.
Even if you do not change any filter value, you can work with the "Scale" values again. Everything goes fluently now.

Win 10, R19.0xx (different version from SP1 to SP3), Corona (different beta 2 versions)

[Beanzvision]

Note to self. Look into.

[Cinemike]

Note to self. Look into.

Don't say I did not give you enough time to look.
It is still horribly slow!

[Cinemike]

Well, it is actually not the "Transform" effect, it is just very slow texture handling of big textures in Corona as soon as the Layer Shader is involved. Unless it is my rig, no idea.
Just compare this:
Create a Corona material, load a layer shader into Diffuse and load a big texture into there.
Now change the Strength slider, again and again. After the first change, things will progress in slow motion.
Try the same with a native C4D material, no lags.

[Cinemike]

A video. The texture is 8k.

[Beanzvision]

I would probably suggest lowering the preview size for now ;)
https://streamable.com/l3p62

[Cinemike]

I would probably suggest lowering the preview size for now ;)
https://streamable.com/l3p62

I hope it is just a workaround, not the final solution. But maybe, for now, you could lower the default value for Corona materials?