Minimum width suggested (3) versus (2)

Hello,

Writing an extension built over 5E, i got an error message that i don't understand :

Ruleset Warning: framedef: Top edge width (2) of frame (windowtitle) less than minimum suggested width (3)
Ruleset Warning: framedef: Bottom edge width (2) of frame (windowtitle) less than minimum suggested width (3)
Ruleset Warning: framedef: Middle width (2) of frame (windowtitle) less than minimum suggested width (3)

I don't see where to fix this problem :

Base code (5E) is :
<offset>56,20,54,11</offset>

My change is :
<offset>95,52,146,30</offset>


Thanks for your help.

what is the dimensions of your image?

243x86 px (vs 243x56 px for the 5E windowtitle image)

You have insufficient pixels left for the middle slice.
You have allowed a width of 2px and a height of 4px.

Thanks damned.