Display problems with overlays (on w32 only?)

[Lennart Borgman (gmail)]

In the attached images I have one overlay one character long that has a 
red underline. In the first picture there is only this overlay at that 
point and the display is correct.

In the second picture I have added another overlay, with a slightly blue 
background. This overlay is 10 characters long and includes a new line. 
The first overlay with the red underline is still just one character 
long, but the red underline now displays in the whole range of the 
second overlay. (The two oeverlays starts at the same character.)

Is this perhaps a simple typo somewhere in the display code?

<<<<<<<<<<<<<<<<<<<<
Here is the output from C-u C-x =

  character: C-j (10, #o12, #xa, U+000A)
    charset: ascii (ASCII (ISO646 IRV))
 code point: #x0A
     syntax:    which means: whitespace
buffer code: #x0A
  file code: #x0A (encoded by coding system undecided-unix)
    display: by this font (glyph code)
     -outline-Courier 
New-normal-r-normal-normal-13-97-96-96-c-*-iso8859-1 (#x0A)

There are 2 overlays here:
 From 786 to 787
  category             rng-error
  help-echo            "<? not followed by name"
  priority             786
 From 786 to 796
  face                 mumamo-background-chunk-submode
  mumamo-major-mode    fundamental-mode
  mumamo-narrow        nil
  priority             100


There are text properties here:
  fontified            t
  nxml-inside          processing-instruction
>>>>>>>>>>>>>>>>>>>>>

And the output when clicking on rng-error:

<<<<<<<<<<<<<<<<<<<<
Category rng-error:

  face                 rng-error-face
  modification-hooks   (rng-error-modified)

[back]
>>>>>>>>>>>>>>>>>>>>>

Dito mumamo-background-chunk-submode:

<<<<<<<<<<<<<<<<<<<<
Face: mumamo-background-chunk-submode (sample) (customize this face)
Documentation: Background colors for chunks in major mode.
You should only specify :background here, otherwise it will
interfere with syntax highlighting.

FIX-ME: background colors for dark cases.
Defined in `mumamo.el'.

         Family: unspecified
          Width: unspecified
         Height: unspecified
         Weight: unspecified
          Slant: unspecified
     Foreground: unspecified
     Background: azure
      Underline: unspecified
       Overline: unspecified
 Strike-through: unspecified
            Box: unspecified
        Inverse: unspecified
        Stipple: unspecified
Font or fontset: unspecified
        Inherit: unspecified

[back]
>>>>>>>>>>>>>>>>>>>>>


In GNU Emacs 22.0.98.1 (i386-mingw-nt5.1.2600)
 of 2007-04-22
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --cflags -Ic:/g/include'