Fixed some long-standing bugs in switching between text and graphics windows (didn't affect xterms, but did affect certain vt100/tek emulators).
Fixed some long-standing bugs in switching between text and graphics windows
(didn't affect xterms, but did affect certain vt100/tek emulators).

svn path=/trunk/; revision=151

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