for me it works at windows 10 within full screen,agk goto window mode , i see the selector and after this it go into fullscreen, but i started it via key press.
maybe try with MinimizeApp() RestoreApp()
the problem is if the file dialog is open and then if the user click in the screen area around this dialog , this window get the focus and the dialog is behind
rem
rem AGK Application 2.0.21
rem MR
#option_explicit
SetWindowSize(800,600,1)
SetVirtualResolution(100,100)
do
if GetRawKeyPressed(65)
print("A")
SelectImage()
endif
if GetPointerPressed()
exit
endif
Sync()
loop
end
function SelectImage()
//MinimizeApp()
local image as integer
if ShowChooseImageScreen()=1 //Ok
while IsChoosingImage()=1 //Dialog is Open, Wait
sync()
endwhile
image = GetChosenImage() //Get the image
endif
//RestoreApp()
endfunction image
AGK (Steam) V2.0.21 : Windows 10 Pro 64 Bit : AMD (16.6) Radeon R7 265 : Mac mini OS Sierra (10.12)