Fixed obscure bug that was causing the plframe to not be properly redisplayed after a zoom in some cases.
Fixed obscure bug that was causing the plframe to not be properly
redisplayed after a zoom in some cases.

svn path=/trunk/; revision=1688

FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot