**System Information**
Windows 10 and OSX 10.11.2
**Blender Version**
Broken: 2.77 (ec99778)
**Short description of error**
If I set the render border in the `render_pre` callback, the value is not valid for this render. Instead I have to render once again to have it being used.
**Exact steps for others to reproduce the error**
Open this file and render: {F290651}, the border will only be "used" the second time you render it
The file simply has the following script (make sure the script runs):
```
import bpy
@bpy.app.handlers.persistent
def render_pre(scene):
scene.render.use_border = True
def main():
scene = bpy.context.scene
scene.render.use_border = False
scene.render.border_min_x = 0.5
bpy.app.handlers.render_pre.append(render_pre)
main()
```