The popup help designer included with Helpstudio is an AddIn for Visual Basic 6 that allows you to create popup help (otherwise known as What's This help - click the help icon on a windows taskbar and point at a field). It is a kind of super tooltip - it opens above the application and closes when you click elsewhere.
There is also a VB6 Context Id Mapper tool available from the VB6 IDE that allows forms and controls to be mapped to topics in your help file for F1 help.
Finally, if your are developing applications with C++ or Delphi, HelpStudio also includes a Context Id mapper tool that is available from the tools menu in HelpStudio itself - this allows you to tie up the application context ids to topics in your help system so that when users press F1 in your application the help file is opened at the right topic. This tool uses a .h file to identify the context ids.
If you are using .NET, the built in .NET HelpProvider control allows you to identify the target help topics for controls and forms.