Opera 12.18, taskbar pane gets erroneously unpressed whenever we open the options dlg

In general the taskbar activation is not that bad in ros for most apps, but I observed a rather interesting malfunction when using Opera 12.18 from rapps.

Observed result
Initially its taskbar pane is properly pressed,
but as soon and every time I open the options-dlg, the taskbar pane gets unpressed erroneously.
0.4.13-RC-46-gbb9997c_Opera12_18_fails.webm
0.4.13-RC-46-gbb9997c_Opera12_18_fails.log

Expected result
I double-checked: This bug does not happen on XPSP3 and also not on 2k3sp2
2k3sp2_opera12_18.webm
Please notice that the minimize/maximize-alternation via taskbar does only work properly in 2k3sp2 when the options-dlg was closed beforehand

I double-checked, this problem happens with:
0.4.13-RC-46-gbb9997c vanilla
0.4.13-RC-46-gbb9997c + explorer-workaround of DougLyons from CORE-16703 taskswnd_c_hack
0.4.13-RC-46-gbb9997c + patch of blueghost from CORE-16703 ntuser_focus2.patch
0.4.14-dev-1012-g820dbfc master head vanilla

Eventually the ticket is a duplicate of CORE-16705, but I am not sure about that, that's why I filed individual tickets.