VLAN configuration on M4300, trunk vs. VLAN participation

[milp]

Looking at the text configuration of a M4300-8x8F stack, I see those two interface definitions:

[...]

interface 1/0/6
description 'uplink sw-cbs3 1/0/1 FO'
switchport mode trunk
exit

[...]

interface 1/0/8
description 'PP DF FO 3018'
switchport mode trunk
vlan ingressfilter
vlan participation include 9,47,99-101,192,194-195,200-204,220,222,250-254
vlan participation include 913,999,1011-1012
vlan tagging 47,99-101,192,194-195,200-204,220,222,250-254,913,999,1011-1012
exit

Question 1:
Is the configuration of interface 1/0/8 actually valid? It is at the same time a trunk (same as 1/0/6), but there are also VLAN's defined. What would a switch do in this case? Adher to "switchport mode trunk" or rather to the VLAN definitons? 

This happened after configuring via Web GUI over time. Fact is that VLAN 1011 and 1012 will not be forwarded.

In the GUI I see this, and that looks pretty strange to me:

Pay attention to VLAN 9, 1011 and 1012. This VLAN's seem to be excluded from "Tagged VLANs". Is this a bug, a feature or do I simply misunderstand the conxcept?

Question 2:
Is there a CLI way to make the interface 1/0/8 identical to the interface 1/0/6 in terms of being in trunk mode only? Or can I do it somehow via the GUI (which behaves quite strangly, btw.)?

If possible without cutting me off, because I sit behind 1/0/8 on VLAN 1.

Thanks.

Dan