ModalWindowRegion not displaying correctly on startup

We are trying to implement a disclaimer popup, using a custom module, that will appear when the user first loads the application.  The module is set to display in the ModalWindowRegion.  The module has been added to the json.js file (libaries and modules sections) and it does seem to load without errors but sometimes the dialog seems to lose focus and never quite gets created properly.  When this happens, firebug will show the dialog as having a css class of 'inactive' which I assume is being applied by some other module since it's not part of our module's code.  Below are screenshots of what it should look like and what it looks like when the load doesn't work properly.

If we load the disclaimer into a different region (such as HomePanelContainerRegion) it seems to load properly every time.

Is there a way to delay the load of a custom module so that it loads after the site has been completely initialized (and before any startup script runs)?

/customer/servlet/servlet.FileDownload?file=00P6000000em15uEAA

/customer/servlet/servlet.FileDownload?file=00P6000000elu9QEAQ