DOCS BUG: Show dialog not documented to a point where it's usable

[BryanCrotaz]

https://wixtoolset.org/docs/schema/wxs/show/

After and Before both say you have to specify the action - what is the action enumeration?
Condition: What's the format of a condition string?
OnExit: Show the dialog Mutually exclusive with Before, After, and Sequence attributes - I have no idea how to parse that to make any sense. Assume there's a full stop after Show the dialog but why would OnExit show the dialog? What do the four options do?

[BryanCrotaz]

My best guess was to modify a sample online https://www.advancedinstaller.com/versus/wix-toolset/create-wix-custom-dialog-user-input.html

<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
  <Fragment>
	  <UI Id="CustomSetupUI">
		  <TextStyle Id="RobotoBold" FaceName="RobotoBold" Size="10" />
		  <Property Id="DefaultUIFont" Value="RobotoBold" />
		  <DialogRef Id="LicenceDlg"/>
		  <TextStyle Id="TahomaWelcome" FaceName="Tahoma" Size="14" Bold="yes" />
		  <TextStyle Id="TahomaInput" FaceName="Tahoma" Size="10" />
		  <Dialog Id="SetupDlg" Width="300" Height="200" Title="Register your new Agent">
			  <Control Id="WelcomeMsg" Type="Text" X="45" Y="40" Width="250" Height="80" Transparent="yes" Text="{\TahomaWelcome}Welcome to the Setup Wizard"/>
			  <Control Id="Info" Type="Text" X="27" Y="80" Width="300" Height="80" Transparent="yes" Text="{\TahomaInfo}Click 'Next' to continue or 'Cancel' to exit the Setup Wizard"/>
			  <Control Id="InstallBtn" Type="PushButton" Text="Next" Height ="25" Width="60" X="165" Y="130">
				  <Publish Event="EndDialog" Value="Return" />
			  </Control>
			  <Control Id="CancelBtn" Type="PushButton" Text="Cancel" Height ="25" Width="60" X="80"  Y="130" Cancel ="yes">
				  <Publish Event="EndDialog" Value="Exit" />
			  </Control>
		  </Dialog>
	  </UI>
	  <InstallUISequence>
		  <Show Dialog ="LicenceDlg" Before="ExecuteAction"/>
	  </InstallUISequence>
  </Fragment>
</Wix>

However the dialog isn't shown when I run the MSI.

[BryanCrotaz]

What are the other options other than ExecuteAction?

[BryanCrotaz]

I've tried the following, with no luck:

• OnStart
• OnExit
• BeforeExecute
• BeforeExecuteAction
• AfterStart

[BryanCrotaz]

On a brainwave, I tried using the Id of a custom action, dialog still doesn't show.