# euse -E gtkhtml webkit
/etc/make.conf was modified, a backup copy has been placed at /etc/make.conf.euse_backup
Gentoo_x64n ~ # emerge mono-tools -av
These are the packages that would be merged, in order:
Calculating dependencies... done!
[ebuild UD] dev-dotnet/libgdiplus-2.4.2 [2.6] USE="cairo" 1,930 kB
[ebuild N ] net-libs/webkit-gtk-22.214.171.124 USE="doc gstreamer websockets (-aqua) -coverage -debug -test" 0 kB
[ebuild UD] dev-lang/mono-2.4.3 [2.6.3] USE="moonlight -minimal -xen" 24,378 kB
[ebuild N ] dev-dotnet/gluezilla-2.4.2 281 kB
[ebuild N ] dev-dotnet/gtkhtml-sharp-2.24.0-r10 USE="-debug" 0 kB
[ebuild N ] dev-dotnet/webkit-sharp-0.2-r1 80 kB
[ebuild UD] virtual/monodoc-2.4.3 [2.6.3] 0 kB
[ebuild N ] dev-util/mono-tools-2.4.2-r1 USE="gtkhtml webkit xulrunner" 969 kB
Total: 8 packages (3 downgrades, 5 new), Size of downloads: 27,636 kB
!!! One or more updates have been skipped due to a dependency conflict:
('ebuild', '/', 'dev-lang/mono-126.96.36.199', 'merge') conflicts with
~dev-lang/mono-2.4.3 required by ('ebuild', '/', 'virtual/monodoc-2.4.3', 'merge')
Would you like to merge these packages? [Yes/No] ^C
Exiting on signal 2
Why it downgrades mono from 2.6 to 2.4.3???
It appears that you manually keyworded mono and a few surrounding apps, but did not do the same for mono-tools. 2.6.1 is available and has the same keywords as mono, so it's a configuration issue on your end.
Yes, after unmasking dev-util/mono-tools it works