On a similar note, is there a call-back for LABKEY.requiresExt4Sandbox()?

Because it seems as if Ext 4 is not finished loading and I am already using Ext4 elements within my main JS code file.

My structure is the following:

LABKEY.requiresScript('LoadLibraries.js', true, flowGraph);

flowGraph calls LABKEY.requiresScript('flowGraph.js', true, <pass the web part div into it here>) and it's 'flowGraph.js', which contains references to Ext4

Now withing 'LoadLibraries.js' I have a line: LABKEY.requiresExt4Sandbox()

Am I not doing something correctly?
(I've already had the same or similar issue in the past, but it went away or may be was well hidden)

Thanks.