WoW Classic XML Error: Unrecognized attribute "relativeFrom" in GreenWall.xml (line 116)

When running the GreenWall addon in WoW Classic (version v1.11.16+classic-era), the following error appears repeatedly in the logs:

GreenWall/GreenWall.xml:116 Unrecognized XML attribute: relativeFrom

It appears that the XML parser in WoW Classic does not recognize the relativeFrom attribute used in the Anchor element for the slider configuration. In the affected file (see GreenWall.xml around line 116), the Anchor for the slider is defined as follows:

<Anchor point="TOPLEFT" relativeTo="$parentOptionRoster" relativeFrom="BOTTOMLEFT">
  <Offset>
    <AbsDimension x="8" y="-64"/>
  </Offset>
</Anchor>

Steps to Reproduce:

• Install the GreenWall addon (v1.11.16+classic-era) in your WoW Classic AddOns folder.
• (Optional) Install the Bugsack and Buggrabber Addons for easy error viewing.
• Launch WoW Classic.
• Observe the error message in the error log (206 instances of the same error).

Expected Behavior:

The addon should load without any XML errors. The slider should be anchored correctly without using any unsupported XML attributes.

Additional Context:

This issue appears to be specific to the WoW Classic version of the addon, that attribute isn't present on the main branch.