ヒラギノさんの参考先のスクリプトを一か所変更して枠を消す部分を追加しただけでで動きましたが
#module
#uselib "gdi32.dll"
#cfunc CreatePatternBrush "CreatePatternBrush" int
#func DeleteObject "DeleteObject"
#func SetBkMode "SetBkMode" int,int
#func SetBrushOrgEx "SetBrushOrgEx" int,int,int,int
#uselib "user32.dll"
#func GetWindowRect "GetWindowRect" int,int
#func MapWindowPoints "MapWindowPoints" int,int,int,int
#deffunc UpdateBackgroundBrush
if ginfo_sel >= length(hBrush) : hBrush.ginfo_sel = 0
if hBrush.ginfo_sel : DeleteObject hBrush.ginfo_sel
mref bmscr,67 : hBrush.ginfo_sel = CreatePatternBrush(bmscr.7)
oncmd gosub *OnCtlColor, 0x133 //WM_CTLCOLOREDIT
return
*OnCtlColor
oldSel = ginfo_sel : gsel ginfo_intid : dim rect,4
SetBkMode wParam, 1 // TRANSPARENT
GetWindowRect lParam, varptr(rect)
MapWindowPoints 0, hWnd, varptr(rect), 2
SetBrushOrgEx wParam, -rect.0, -rect.1, 0
gsel oldSel : return hBrush.ginfo_intid
#global //// モジュここまで
picload dir_exe + "/sample/demo/sky_bg.jpg"
UpdateBackgroundBrush
#include "user32.as"
a = "AAAAAAAAAAAAAAAA"
input a, 200
hInput = objinfo(stat, 2)
GetWindowLong hInput, -20
SetWindowLong hInput, -20,stat & $FFFFFDFF
SetWindowPos hInput, 0, 0, 0, 0, 0, $0027