Check Box colour problem in Forms v4/Oracle 7

Hi Oracle Gurus!

As an Internet and Oracle newbie I appreciate that this may seem a silly question to most of you, but...

We are developing an application using Oracle 7 Server for Netware. We are creating forms using Oracle Forms Designer (for Windows) v.4.0.12.1.10 and Oracle Virtual Graphics System v2.0.16.4.0.

When we create Check Boxes on the form:
(a) the Transparent Fill option doesn't appear to work at all
(b) any background colour requested comes out half a tone lighter than
anticipated.

We've tried modifying the form under Win95 and WFW 3.11, in 800x600 and 1024x768 modes and in 65535 and 256 colour modes. None of which appear to affect the problem.

Are we missing something obvious (or even, not so obvious) here? Is this a known 'feature'?
Is there any way of working around it?

Please help me or put me out of my misery!

TIA

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John M. Smith__________oOO_(_)_OOo__________John_at_p5-90.demon.co.uk