Please describe the problem:
Hi!
The great image preview (have found in buglist that the feature is relatively
new, bug 55367) completely ignores the transparency (opacity) setting and
enforces only the active layer be visible.
That is IMPORTANT misfeature, at least for two types of photo images made "by hand":
- stereoscopic images (in first stage the images must be aligned)
- HDR (high resolution images), when photos with differrent exposition are
overlayed.
Additionally the unresolved bug: 129379 – remember center of rotation disallows
event the dumb "do a step, check what happens, reverse and modify size of the
step" work is impossible; I am agree that will be sufficient, when the rotation
tool will save center position - but it also does not that!

Regards - Gotfryd Smolik
"the best resolution for the 129379 bug may be 

Steps to reproduce:
1. get any 2-layer image
2. set 50% opacity on the top layer
3. select rotation tool and image preview
4. rotate the top layer


Actual results:
while rotation starts the underlying layer is NOT visible anymore

Expected results:
The opacity setting must be honoured while preview; there may be great a
separate option to allow the current behaviour, where may be useable for other
work; of course, other tools (b.ex. move) does not allow the behaviour for
rotate tool, then probably that is not important

Does this happen every time?
Yes, but I am only Windows GIMP user, dont have clue if that depends od system
specific libraries.

Other information:
Yes, excuse my horrible English :)