The following bug has been logged online:
Bug reference:      5953
Logged by:          martin van leeuwen
Email address:      vanleeuwen(dot)martin(at)gmail(dot)com
PostgreSQL version: 9.0.2-1-win-x84
Operating system:   windows 7 enterprise SP1
Description:        pgadmin sql-query text pad doesn't work
Details: 
The text input for sql query tool in pgadmin stopped working today (26 mrch
2011) and was succesfully used the last time on 22 mrch 2011.