Qt Assistant shows empty page for small html documentation files (<512 bytes)

Qt Assistant shows empty page for small html documentation files.

Steps to reproduce:

• Get Qt_SDK_Win_offline_v1_2_en.exe for Windows
• Compile example from source code distribution qt-qt-4.8.tar.gz, qt-qt/examples/help/contextsensitivehelp/doc/wateringmachine.qhcp
  qcollectiongenerator.exe wateringmachine.qhcp -o wateringmachine.qhc
• Displaying obtained collection with Assistant shows only some pages of docs, those bigger of 512 bytes.
  assistant.exe -collectionFile wateringmachine.qhc

Reproducible with precompiled binaries from SDK setup sections Desktop Qt 4.8.0 MSVC 2008, Desktop Qt 4.8.0 MSVC 2010, and Desktop Qt 4.8.0 MinGW.

Assistant of version Qt 4.7.4 distributed with the same packages fails completely with assertion - I couldn't even open help file to check if it works.