gem bug - single buffering

[Mark Danks]

  Someone noticed that GEM has a bug where nothing appears to be drawn
in single buffering mode.

  I have a fix for the bug and will put it in the next release, unless
someone wants/needs it earlier.

Later, Mark

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-- Mark Danks
-- mdanks at stormfront.com
-- http://www.danks.org/mark
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