The Fade plugin causes new windows with opacity=0.0 to briefly flash on the screen

[Sami Jaktholm]

STR:
1. Download the attached testcase (testcase.c) and install libgtk-3-dev package.
2. Compile it: gcc `pkg-config --cflags gtk+-3.0` -o testcase testcase.c `pkg-config --libs gtk+-3.0`
3. Run the testcase: ./testcase

What happens: When the testcase is executed the black rectangle appears briefly before fading out.
What should happen: When the testcase is executed a black rectangle should not appear as the window is fully transparent.

If I disable the fade plugin everything works as it should: the fully transparent window is transparent the whole time.

Firefox will be using this kind of technique (the testcase is based on the Firefox implementation) to create an enter-to-fullscreen (and exit) animation in future releases (it's at least in Nightly at the moment). So every time you go full screen for example in YouTube this bug in the fade plugin causes extra flickering as they initially a transparent window is first shown and then faded out by the plugin before Firefox fades it in itself.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: compiz 1:0.9.11.3+14.04.20150313-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-66.108-generic 3.13.11-ckt27
Uname: Linux 3.13.0-66-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.18
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CurrentDesktop: Unity
Date: Wed Oct 28 17:36:02 2015
PackageArchitecture: all
SourcePackage: compiz
UpgradeStatus: No upgrade log present (probably fresh install)