Thanks for the reply,
Did not help
No difference to either the save or open dialogs, now version 1.5.0
After killing the unresponsive calibre I get this information:
Problem Event Name: AppHangB1
Application Name: calibre.exe
Application Version: 1.5.0.0
Application Timestamp: 5243ae8f
Hang Signature: f0fc
Hang Type: 0
OS Version: 6.1.7600.2.0.0.256.1
Locale ID: 1033
Additional Hang Signature 1: f0fc05bb35c3e80972be389375f7ab82
Additional Hang Signature 2: 9fa0
Additional Hang Signature 3: 9fa0dbd7a504ed28544bc2f4865918b3
Additional Hang Signature 4: f0fc
Additional Hang Signature 5: f0fc05bb35c3e80972be389375f7ab82
Additional Hang Signature 6: 9fa0
Additional Hang Signature 7: 9fa0dbd7a504ed28544bc2f4865918b3