Description
As a new feature in APM 2.50, Tool Tips are now displayed in the Tool Configuration dialogs for the compiler, assembler and linker, showing the command-line equivalent for each selectable option. For example:

1. Open a project, for example, c:\arm250\examples\Dhry\dhry.apj 
2. In the Project menu choose Tool configuration for dhry.apj -> cc = armcc -> Set. The Compiler Configuration property sheet appears.
3. Select the Target page tab.
4. Move the mouse cursor arrow to rest over the Little Endian radio button in the Byte Sex group box top left in the Target page. A Tool Tip containing -littleend should appear for a while then disappear. If it does not, then APM is using a different Microsoft Foundation Class DLL version from the one redistributed with SDT 2.50/2.51.

SDT 2.50/2.51 requires two DLLs (MFC42.DLL and MSVCRT.DLL) to be present on a Windows system. These DLLs are supplied on the SDT 2.50/2.51 CD-ROM, and are normally placed into the Windows System32 directory during installation, unless a later version (installed by another application), already exists there. However, some later versions of these DLLs have tooltips broken, so you may find that the Tool Tips for APM's Tool Configuration dialogs do not work.

• With MFC42.DLL 4.21.7022, tooltips are working
• With MFC42.DLL 4.21.7160, tooltips are broken

You can check the version using Windows Explorer to view MFC42.DLL's properties (via context menu or ALT+Enter) and select the Version page.

Solution
The DLLs (with working tooltips) are also copied into the SDT directory (typically c:\arm250\). If your system suffers with tooltips not working, then simply copy these DLLs from the SDT directory into the SDT Bin directory (typically c:\arm250\bin\). When APM (which also resides in c:\arm250\bin\) is restarted, it will use the DLLs in the SDT Bin directory instead of the DLLs in the Windows System32 directory.

Other applications which possibly require MFC42.DLL with a higher version number (for example, Microsoft Visual C++ 5.0) are unaffected, because they will still use the DLLs in the Windows System32 directory. However, your Virtual Memory requirements may increase slightly because SDT 2.50/2.51 will then no longer share MFC42.DLL with other applications.