going wrong, and that is what this compatibility bitflag does. Don't send calcsize WM_MOVEThis is bit #17 of the compatibility bits word, with hexadecimal value 0x20000, known by the symbolic name GACF_NCCALCSIZEONMOVE in . This flag forces the WM_NCCALCSIZE message to be sent to a window that is being moved or resized. This is the Windows 3.0 behaviour. In Windows 3.1, the behaviour was changed so that the window message is only sent to those windows that were being resized. It was not sent if the window was merely moved. Some Windows 3.0 applications, however, such as Lotus Notes for example, relied upon always receiving this message. Enum Helv and Times Roman fontsThis is bit #12 of the compatibility bits word, with hexadecimal value 0x1000, known by the symbolic name GACF_ENUMHELVNTMSRMN in . This flag works around a problem with applications that refused to work properly unless fonts with the exact names "Helv" and "Tms Rmn" were listed as present on the system by the Windows font enumeration API. The names are trademarks of Linotype company for particular fonts, Helvetica and Times Roman, and since Microsoft didn't ship those Linotype fonts with Windows 3.1, it could not enumerate them as present. This flag causes Windows to enumerate the "MS Sans Serif" and "MS Serif" fonts under the names "Helv" and "Tms Rmn", for compatibility with the applications that don't work without those exact names being used. Force extra windows wordsThis is bit #8 of the compatibility bits word, with hexadecimal value 0x100, known by the symbolic name GACF_MOREEXTRAWNDWORDS in . This flag works around a problem with applications that assumed the existence of window words (extra items of data associated by Windows with GUI windows) when they had not in fact informed Windows that extra window words were required. Windows 3.1, unlike Windows 3.0, bounds checks all uses of extra window words, and applications that assumed that they could use more space than they had asked for would thus fail. For applications run with this flag set, Windows 3.1 silently increased the total number of words requested by the application by an extra 4 bytes. Force printer text to new bandThis is bit #1 of the compatibility bits word, with hexadecimal value 0x2, known by the symbolic name GACF_FORCETEXTBAND in . This flag causes Windows 3.1 to always use two bands when printing, the first for graphics and the second