nodes_to_remove = []
for vop_type in hou.vopNodeTypeCategory().nodeTypes().values():
    for node in vop_type.instances():
        if node.parent().isMaterialManager() and not node.dependents():
            nodes_to_remove.append(node)

if nodes_to_remove:
    ids = hou.ui.selectFromList([ node.name() for node in nodes_to_remove ],
                                default_choices=range(len(nodes_to_remove)),
                                title="Remove Unused Materials", column_header="Unused Nodes",
                                clear_on_cancel=True, height = hou.ui.scaledSize(500))
    
    [ nodes_to_remove[id].destroy() for id in ids ]

import os
from hutil.Qt.QtWidgets import QMenu
from hutil.Qt.QtGui import QCursor
from hutil.Qt.QtCore import QPoint

def getRecentHipFiles():
    userdir = hou.getenv('HOUDINI_USER_PREF_DIR')
    file = os.path.join(userdir, "file.history")
    
    validfiles = []
    with open(file) as f:
        lines = f.readlines()
        for line in lines:
            newline = line.strip()
            if newline == "}":
                break;
                
            if newline != "{" and newline != "HIP":
                if os.path.exists(newline):
                    validfiles.append(newline)
        
    validfiles.reverse()
    return validfiles
    
files = getRecentHipFiles()

if files:
    menu = QMenu(hou.qt.mainWindow())
    menu.triggered.connect(lambda action: hou.hipFile.load(action.text()))
    [ menu.addAction(f) for f in files ]
    menu.setActiveAction(menu.actions()[0])
    menu.exec_(QCursor.pos() - QPoint(hou.ui.scaledSize(8), hou.ui.scaledSize(8)))

import os

def getRecentHipFiles():
    userdir = hou.getenv('HOUDINI_USER_PREF_DIR')
    file = os.path.join(userdir, "file.history")
    
    validfiles = []
    with open(file) as f:
        lines = f.readlines()
        for line in lines:
            newline = line.strip()
            if newline == "}":
                break;
                
            if newline != "{" and newline != "HIP":
                if os.path.exists(newline):
                    validfiles.append(newline)
        
    validfiles.reverse()
    return validfiles

files = getRecentHipFiles()
    
if files:
    ids = hou.ui.selectFromList(files, default_choices=(0,), exclusive=True,
                                title="Open Recent Scene", column_header="Recent Scenes",
                                clear_on_cancel=True, width=hou.ui.scaledSize(700))
    
    if ids:
        hou.hipFile.load(files[ids[0]])

nodes_to_remove = []
for vop_type in hou.vopNodeTypeCategory().nodeTypes().values():
    for node in vop_type.instances():
        if node.parent().isMaterialManager():
            no_refs = True
            for parm in node.parmsReferencingThis():
                if parm.node() != node:
                    no_refs = False
                    break
            if no_refs:
                nodes_to_remove.append(node)

if nodes_to_remove:
    ids = hou.ui.selectFromList( [ node.name() for node in nodes_to_remove ],
                                 default_choices=range(len(nodes_to_remove)),
                                 title="Remove Unused Materials", column_header="All Unused Nodes",
                                 clear_on_cancel=True, height=hou.ui.scaledSize(500) )
    
    [ nodes_to_remove[id].destroy() for id in ids ]

EDITORS = {
    
'PyCharm' : 'C:/Program Files/JetBrains/PyCharm Community Edition 2021.1.1/bin/pycharm64.exe',
'Sublime' : 'C:/Program Files/Sublime Text 3/sublime_text.exe'

}

editor_id = hou.ui.displayMessage("Please choose your weapon.", buttons=tuple(EDITORS.keys()))
editor_path = tuple(EDITORS.values())[editor_id]

# set editor 1 for alt-e / HDA script edit
hou.putenv("EDITOR", editor_path)

# set editor 2 for right click edit in external editor
with open(hou.homeHoudiniDirectory() + "/ExternalEditor.cfg", 'w') as f:
    f.write(editor_path)

labels_list = []
for k in ext_dict.keys():
    labels_list.append(k)