Regression - Gecko is not downloaded and not installed during 2nd stage setup

VBox 4.3.40, official gcc dbg builds

Expected result:
when selected during 2nd stage setup, Gecko is downloaded and installed

Observed result
when selected during 2nd stage setup, Gecko is not downloaded and not installed, the Window just closes automatically

a regression and I am currently hunting the guilty rev
noGecko_RegressionTest.txt

Good-path log:
reactos-bootcd-0.4.10-dev-87-gc8ea82d-x86-gcc-lin-dbg__GeckoInstalledOk.log

Bad path log:
reactos-bootcd-0.4.10-dev-435-gfb5d5ec-x86-gcc-lin-dbg__noGeckoInstall.log