Conflict between Blender 3D and KDE: KDE ignore my settings

(First, excuse me if ever my english was bad but that's not my usual langage.)

I'm trying to disable the Alt+click shorcuts of KDE 4.8.4 / Plasma 5.77 (for displace window) because of a conflict with Blender 3D shortcut. I've tried to follow this wikibooks instructions:

http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Operating_System_specific_notes

1) Right click on the title bar of the main Blender window → select Configure Window Behavior → go to Actions → Window Actions → in the Inner Window, Titlebar and Frame section → select the Modifier key to be ALT and set all the select boxes beneath it to Nothing.

2) Right click on the title bar of the main Blender window; then select Advanced → Special Application Settings... → Workarounds and then click Block global shortcuts with Force selected and checked.

My first obstacle is that the menu immediately disappear when I right click on the title bar of any window  . But I guess that passed by the System Settings is the same, so:


First Method : I find "Window Behavior">"window Actions">"Inner Window, Titlebar and Frame":
I tried once by changing "Alt" by "Meta" and once by keeping "Alt" and set all buttons actions to 'nothing', I've tried that in usual and root mode without any effect!  

Second Method : the search engine of system settings give me no response for "Advanced" or "Special Application Settings". for "Workarounds", I redirect to "Window Behavior">"Window Rules">"modify" or "new" >"Appearence & fixes">"Ignore Global Shortcuts"> "forced" & "yes". One more time, I've try it in usual and root mode without success!  

So, do someone can explain me why KDE ignore my setting and how I can fixe this?

(I'm on Debian 7.6 with 3.2.0-4-amd64 #1 SMP Debian 3.2.60-1+deb7u1 x86_64 GNU/Linux core)

Source:https://forum.kde.org/viewtopic.php?f=17&t=122075