ID 134367 - *[PUBLIC] User knobs on the root node should be removed by nuke.scriptClear()

Problem summary
scriptClear/scriptClose does not remove user created knobs from Root.

Customer reported version
nuke.10.5v6

Customer reported platform
centos7

Steps to reproduce
1) Open Nuke. 
2) Open a Script Editor (Right click the top bar of any pane > Script Editor).
3) Copy and paste the following code into the Script Editor and run it (Ctrl + Enter):

user_knob = nuke.Double_Knob('user_knob', 'Slider')nuke.root().addKnob(user_knob)nuke.scriptClear()print 'user_knob' in [knob.name() for knob in nuke.root().allKnobs()]

4) Notice that the script returns "True". It should return "False".

Reproduced by Support in:

Nuke 13.0v4 - Windows 10, macOS 10.14

Nuke 13.0v1 - Windows 10

Nuke 12.0v1 - Windows 10

Nuke 11.0v1 - Windows 10 

Nuke 10.5v7 - Windows 10

Nuke 10.5v1 - Windows 10

Nuke 10.0v6 - Windows 10

Nuke 10.0v1 - Windows 10

Nuke 9.0v9 - Windows 10

Nuke 9.0v1 - Windows 10

Nuke 8.0v7 - Windows 10

Nuke 8.0v1 - Windows 10, Mac OSX El Capitan - Linux CentOS 6
 

Earliest version tested
Nuke 8.0v1 - This issue appears to be in all versions of the product
 

Workaround:

Adding an onDestroy() callback for the root node class allows the User knobs to be cleared with a specific function. Place the following example in the .nuke/menu.py

Example:

def removeUserTab():    '''Function to remove the User tab in root with all knobs (tested up to 60 user knobs removed in one shot).    '''    n = nuke.root()    while n.knob('User').name() == "User":        for name in n.knobs():            try:                for each in n.knobs():                    if n.knobs()!= "User":                        n.knobs().get(name).node().removeKnob(n[name])                        n.knobs().get('User').node().removeKnob(n['User'])            except Exception:                pass        breaknuke.addOnDestroy(removeUserTab, nodeClass='Root')

Expected behavior
When the following code is run, it should return "False".

user_knob = nuke.Double_Knob('user_knob', 'Slider')nuke.root().addKnob(user_knob)nuke.scriptClear()print 'user_knob' in [knob.name() for knob in nuke.root().allKnobs()]

Actual behavior

When the following code is run, it returns "True".

user_knob = nuke.Double_Knob('user_knob', 'Slider')nuke.root().addKnob(user_knob)nuke.scriptClear()print 'user_knob' in [knob.name() for knob in nuke.root().allKnobs()]