SITUATION
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I am building a simple editor using a TextView and TextBuffer.
Adding text to the buffer line by line and then editing
this text. 

ERROR
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Empty lines are missing in the TextView, the behaviour is wrong 
and assert-failures are generated on the console.(stderr/stdout?)
OBS! Works just fine when compiled & run in Linux (RH9)

REPRODUCE
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When walking from line to line using cursor keys there is 
sometimes a hidden position before the beginning of the 
line, reachable by hitting left-arrow when in the beginning 
of the line. The cursor dissapears and if i hit down-arrow 
an assertion failure is generated.

ENVIRONMENT
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Windows XP
Dev-C++
GTK+-win32 2.2.1.2 (.exe installer)
gtkmm-2.2.5.1 (.exe installer) (sigc+ bundled in installer is 1.2.5)