How to avoid error messages in Eclipse 2020-03 for GWT ui.xml files (Language Server)

Question

In my GWT 2.8 based project Eclipse 2020-03 shows me lots of error message under Markers -> Language Servers I am sure that these are not errors. For some reason, Eclipse cannot interpret ui.xml files correctly. The application compiles and runs fine:

My eclipse wide settings for XML validation are as follows:

There are not project-specific settings for this

Here is an extract (not the complete source!!!) of one example of a something.ui.xml file. The project contains lots of those files:

<!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent">
<ui:UiBinder 
    xmlns:ui="urn:ui:com.google.gwt.uibinder" 
    xmlns:g="urn:import:com.google.gwt.user.client.ui"
    xmlns:b="urn:import:org.gwtbootstrap3.client.ui"
    xmlns:a="urn:import:com.myapp.client.widgets"
    ui:generateFormat="com.google.gwt.i18n.rebind.format.PropertiesFormat"
    ui:generateKeys="com.google.gwt.i18n.server.keygen.MD5KeyGenerator"
    ui:generateLocales="default" >

<ui:with type="com.myapp.resources.text.CommonMessages" field="msgs" />
<ui:with type="com.myapp.resources.text.SummaryMessages" field="sMsgs" />

<b:Modal closable="true" fade="true" dataBackdrop="STATIC" dataKeyboard="true" 
    b:id="dialog" 
    ui:field="dialog">
    <b:ModalHeader title="{sMsgs.transferOwnership}" />
    <b:ModalBody>
        <g:HTML><ui:text from="{sMsgs.transferOwnershipDescription}"/></g:HTML>

        <b:ListBox 
            ui:field="userListBox"
            multipleSelect="false"
            width="100%"
             />

        <b:Alert type="DANGER" ui:field="participantWarning">
            <b:Icon type="WARNING"/>
            <g:HTML><ui:text from="{sMsgs.transferOwnershipNotParticipantWarning}" /></g:HTML>
        </b:Alert>
    </b:ModalBody>
    <b:ModalFooter>

These are the error messages:

Mouseover on the error always shows:

although it is declared above: [...]

xmlns:b="urn:import:org.gwtbootstrap3.client.ui"

[...]

Import: The application compiles and runs fine. So I just want to suppress those error messages (show in error) as they are not really error messages. :-)

These resources might be helpful:

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Answer 1

You can disable this validation by unchecking the box at Eclipse -> Preferences -> Language Servers -> XML.