Have Checkbox checked by default in UI

I am trying to add a new checkbox into a UI screen for my installer.

So far I have declared the property as seen below:

<Property Id="RS232" Value="1" Secure="yes"/>

And in the UI, my checkbox has been added as:

<Control Id="myNewCheckbox" Type="CheckBox" X="200" Y="170" Text="Generic Driver" Width="130" Height="15" Property="RS232" CheckBoxValue="1"/>

From documentation I have read I am lead to believe that as long as CheckBoxValue and Value are equal i.e 1 in this case, then the checkbox should be checked by default.

There are already existing checkboxes on this same UI and this is true for them, so I do not understand why in my additional case, the checkbox is not active.

Another note to be made is that when I go through the installation process to test the new checkbox, the dialog disappears when I hover over it with a mouse and I am unable to check/uncheck the box.

I first thought that perhaps the Width field for the text was not big enough, but I have tested by expanding this with no results.

Any help is appreciated!