First of all, thanks to @gabarts @sebastian and @AFRLme for the feedbacks
I managed to have something very like SCUMM action text, so I would like to share how it works, if someone needs it too.
SCUMM-Like action text
1) As Sebastian suggests, you will need to have an action on your "Left Click" action, located in the "Cog" menu of Visionaire.
2) The script should look like this:
if object below cursor exists
Save Object
Execute command on saved object
Wait until character 'Current character' stops
Clear saved object
Set standard command
Else
Clear saved object
Set standard command
End if
This way you can have the action text "freezed" until the action is performed.
If you click on a non-existant object, the command will be set to "Walk to" (or your default command).
Optional: highlight text during action
1) Create 2 fonts: call the first one "Font_Action_Diag" and make it grey.
Create the second font: call il "Font_Action_Diag_Highlight" and make it white.
2) Go to "Interface" button in Visionaire.
2a) Create a new interface, call it "Action_Text_Area"
2b) Create a button inside this interface,
2c) choose the Button Type "Action Area".
2d) Draw the text with the [T] icon. Make sure you have "Do not draw action text" as choiche in your Game proprieties tab (Cog icon).
3) Create two execution scripts (you have to go in the { } menu in Visionaire, and uncheck "definition script".
First script: call it "blink"
local activateFont = getObject("Fonts[Font_Action_Diag_Highlight]")
local action_interface = getObject("Interfaces[Action_Text_Area]")
action_interface:setValue(VInterfaceActionTextFont, activateFont)
Second script: call il "blonk"
local activateFont = getObject("Fonts[Font_Action_Diag]")
local action_interface = getObject("Interfaces[Action_Text_Area]")
action_interface:setValue(VInterfaceActionTextFont, activateFont)
4) Modify the script you created before (SCUMM-Like action text, that is inside your mouse left click action) like this:
Call script 'blink'
if object below cursor exists
Save Object
Execute command on saved object
Wait until character 'Current character' stops
Clear saved object
Set standard command
Else
Clear saved object
Set standard command
End if
Call script 'blonk'
That's it
Hope it helps!
PS: I'm not a script Ninja™ like AFRLme, there is a better way to do it for sure