With Delphi XE2 (Update 2) create a Win32 VCL application with a button on a form. Make sure HTMLHelpViewer is in the uses list. In FormCreate set the application help file to a valid CHM help file, e.g.
Application.HelpFile:='C:\path to my help file\help file.chm';
In the buttons OnClick event get it to show the table of contents for the help file:
Application.HelpShowTableOfContents;
Run the application, click the button, the help file appears. Now click on the contents frame on the right (the one that shows the help text for the current topic, not the list of help topics on the left) in the help window and press Ctrl-F to find some text. Nothing happens.
If you open the help file from Explorer then Ctrl-F works as expected.
If I use the same code and help file with Delphi 2007 then Ctrl-F works as expected.
Bug in XE2, or something I've forgotten to set? I tested this in Win7 x64.