I have released a new version, which should work properly, when the window is resized... You can get it under http://jmapview.sourceforge.net/ (& admire the new homepage design )
About the proxy issue: In the path of my Java Runtime Environment (in my case this happens to be C:\Programme\Java\jre6\bin ), there is a file javacpl.exe, which is a control panel for java... In one of the tabs you can change the network settings and specify your proxy server - hth...