Win clipboard problems.

Some time clipboard send empty text to fasm editor window.
And selected text disapiared in fasm editor window.
I found in fasm editor this code

Code:

 wm_copy:
        cmp     [was_selection],0
        je      ignore
        call    copy_to_clipboard
        jmp     ignore
    copy_to_clipboard:
        call    get_block_length
        inc     ecx
        invoke  GlobalAlloc,GMEM_MOVEABLE+GMEM_DDESHARE,ecx
        mov     ebx,eax
        invoke  GlobalLock,ebx
        mov     edi,eax
        push    ebx
        call    copy_block
        pop     ebx
        invoke  GlobalUnlock,ebx
        invoke  OpenClipboard,[hwnd]
        invoke  EmptyClipboard
        invoke  SetClipboardData,CF_TEXT,ebx
        or      eax,eax
        jz      copy_failed
        invoke  CloseClipboard
        retn
    copy_failed:
        invoke  GlobalFree,ebx   ;why free only when  copy_failed ?
        retn

And why fasm editor using GMEM_MOVEABLE+GMEM_DDESHARE ?
And not using only GMEM_MOVEABLE ?
msdn and many tutorials using GMEM_MOVEABLE