I'm trying this dosbox for the shaders and the problem is that when is in window mode it looks great, i can see the shader improving the image BUT when i go to fullscreen the image goes bad, like if it the shader was not there

i have the conf like this, tried the other options but doesn't change anything:

fullscreen = false
fullscreenmode = exklusiv
display= 0
vsync = false
fullresolution= 1920x1080
windowresolution= 1280x960
windowborderless= false
output = opengl
gl.shpath= .\DATA\SHADERS
gl.shader = xBR-LV2
texture.renderer= opengl
UseAspectHeight= true
autolock= true
mmbutton= true
sensitivity = 100
DisableSystemKeys = false
waitonerror = true
priority = higher,normal
mapperfile = \KeyMap.map
Dosbox Shutdown Key = 0
VoodooUseOwnWindowRes = false
VoodooUseOwnFullScRes = false
VoodooDesktopFullScrn = true
WindowsTaskbarAdjust = -5
DisableIntroStartup = false