Major update of all demo programs to use new PEP8 bindings, etc

DemoPrograms old/Demo_Invisible_Elements.py

@@ -0,0 +1,27 @@
+import PySimpleGUI as sg
+
+"""
+    Demonstrates that using a Column Element to make groups of Elements appear and disappear
+    will cause the layout of the elements in the column to remain as they were.  If each individual element
+    were made invisible and then visible, then tkinter puts EACH ELEMENT on a separate row when it is made
+    visible again.  This means a row of 6 elements will become a column of 6 elements if you make each of them
+    visible one at a time.
+
+"""
+
+layout = [[sg.Column([[sg.Text('My Window')],[sg.Input(key='_IN_'), sg.B('My button', key='_OUT_')]], key='_COL_')],
+            [sg.Button('Invisible'), sg.B('Visible'), sg.Button('Exit')]]
+
+window = sg.Window('Window Title', layout)
+
+while True:             # Event Loop
+    event, values = window.Read()
+    print(event, values)
+    if event in (None, 'Exit'):
+        break
+    if event == 'Invisible':
+        window.Elem('_COL_').Update(visible=False)
+    elif event == 'Visible':
+        window.Elem('_COL_').Update(visible=True)
+
+window.Close()