New demo that shows how button states can be managed

Demo_Button_States.py

@@ -0,0 +1,54 @@
+import PySimpleGUI as sg
+"""
+Demonstrates using a "tight" layout with a Dark theme.
+Shows how button states can be controlled by a user application.  The program manages the disabled/enabled
+states for buttons and changes the text color to show greyed-out (disabled) buttons
+"""
+
+sg.ChangeLookAndFeel('Dark')
+sg.SetOptions(element_padding=(0,0))
+
+StartButton = sg.ReadFormButton('Start', button_color=('white', 'black'))
+StopButton = sg.ReadFormButton('Stop', button_color=('gray34','black'))
+ResetButton = sg.ReadFormButton('Reset', button_color=('gray','firebrick3'))
+SubmitButton = sg.ReadFormButton('Submit', button_color=('gray34','springgreen4'))
+
+layout = [[sg.T('User:', pad=((3,0),0)), sg.OptionMenu(values = ('User 1', 'User 2'), size=(20,1)), sg.T('0', size=(8,1))],
+          [sg.T('Customer:', pad=((3,0),0)), sg.OptionMenu(values=('Customer 1', 'Customer 2'), size=(20,1)), sg.T('1', size=(8,1))],
+          [sg.T('Notes:', pad=((3,0),0)), sg.In(size=(44,1), background_color='white', text_color='black')],
+          [StartButton, StopButton, ResetButton, SubmitButton]
+          ]
+
+form = sg.FlexForm("Time Tracker", default_element_size=(12,1), text_justification='r', auto_size_text=False, auto_size_buttons=False,
+                   default_button_element_size=(12,1))
+form.Layout(layout)
+recording = have_data = False
+while True:
+    button, values = form.Read()
+    if button is None:
+        exit(69)
+    if button is 'Start':
+        StartButton.Update(button_color=('gray34','black'))
+        StopButton.Update(button_color=('white', 'black'))
+        ResetButton.Update(button_color=('white', 'firebrick3'))
+        recording = True
+    elif button is 'Stop' and recording:
+        StopButton.Update(button_color=('gray34','black'))
+        StartButton.Update(button_color=('white', 'black'))
+        SubmitButton.Update(button_color=('white', 'springgreen4'))
+        recording = False
+        have_data = True
+    elif button is 'Reset':
+        StopButton.Update(button_color=('gray34','black'))
+        StartButton.Update(button_color=('white', 'black'))
+        SubmitButton.Update(button_color=('gray34', 'springgreen4'))
+        ResetButton.Update(button_color=('gray34', 'firebrick3'))
+        recording = False
+        have_data = False
+    elif button is 'Submit' and have_data:
+        StopButton.Update(button_color=('gray34','black'))
+        StartButton.Update(button_color=('white', 'black'))
+        SubmitButton.Update(button_color=('gray34', 'springgreen4'))
+        ResetButton.Update(button_color=('gray34', 'firebrick3'))
+        recording = False
+