Alt key not working to move window(s) (new PC)

Hello,

I have a new computer and I am trying CTWM on it.

Visibly the new PC does not see the keypress of "ALT" (which is defined as
'm' into button3 defiiontion)

I have a kernel Linux 4.5.5, based on Debian Linux (testing).
ctwm is the default one from debian repositories.

The following three lines are not working (pressing ALT + button of mouse)
does not do anything.
Button1 = m : window|icon : f.function "move-or-raise"
Button2 = m : window|icon : f.iconify
Button3 = m : window|icon : f.function "resize-plus"


I have tried several things with the config but not working still,
unfortunately:(
Maybe it comes from X?



/&///////////////////////////////
I have a simple configuration file.

NoGrabServer
RestartPreviousState
DecorateTransients
TitleFont "-adobe-helvetica-bold-r-normal--*-120-*-*-*-*-*-*"
ResizeFont "-adobe-helvetica-bold-r-normal--*-120-*-*-*-*-*-*"
MenuFont "-adobe-helvetica-bold-r-normal--*-120-*-*-*-*-*-*"
IconFont "-adobe-helvetica-bold-r-normal--*-100-*-*-*-*-*-*"
IconManagerFont "-adobe-helvetica-bold-r-normal--*-100-*-*-*-*-*-*"

#ShowWorkSpaceManager # start with workspace manager up

UseThreeDMenus
UseThreeDTitles
UseThreeDIconManagers
UseThreeDBorders
UseThreeDWMap
SunkFocusWindowTitle

WorkSpaceManagerGeometry        "360x60+60-0" 4
WorkSpaces {
    "One"   {"rgb:0/6/6" "rgb:f/f/f" "rgb:0/6/6" "rgb:f/f/f"}
    "Two"   {"rgb:4/4/6" "rgb:f/f/f" "rgb:4/4/6" "rgb:f/f/f"}
    "Three" {"rgb:6/4/4" "rgb:f/f/f" "rgb:6/4/4" "rgb:f/f/f"}
    "Four"  {"rgb:6/6/6" "rgb:f/f/f" "rgb:6/6/6" "rgb:f/f/f"}
    "Five"  {"rgb:0/4/4" "rgb:f/f/f" "rgb:0/4/4" "rgb:f/f/f"}
    "Six"   {"rgb:2/2/4" "rgb:f/f/f" "rgb:2/2/4" "rgb:f/f/f"}
    "Seven" {"rgb:4/2/2" "rgb:f/f/f" "rgb:4/2/2" "rgb:f/f/f"}
    "Eight" {"rgb:4/4/4" "rgb:f/f/f" "rgb:4/4/4" "rgb:f/f/f"}
}


Function "resize-plus" { f.resize }
Button1 = c : window|icon : f.function "move-or-lower"
Button2 = c : window|icon : f.iconify
Button3 = c : window|icon : f.function "resize-plus"

Button1 = m : window|icon : f.function "move-or-raise"
Button2 = m : window|icon : f.iconify
Button3 = m : window|icon : f.function "resize-plus"
#AutoRelativeResize
AutoRaise

"r"= c|m : all : f.twmrc # Ctrl-Alt-R reloads .ctwmrc
"r"= c : all : f.twmrc # Ctrl-Alt-R reloads .ctwmrc

AutoRelativeResize


Looking forward to hearing you.