XML Parsing Error: prefix not bound to a namespace <- but it is...

[eyalroz]

I'm using an HTML element replacing a XUL element, e.g. <html:input>, e.g. in my preferences dialog. But - when I try to use that dialog, in TB 68, I get an error saying:

XML Parsing Error: prefix not bound to a namespace
Location: chrome://bidimailpack/content/bidimailpack-prefs-68.xul
Line Number 59, Column 7:      <html:input id="space_between_paragraphs_value_text"
------^

This is strange, since I think I did ensure the prefix is bound to a namespace. My dialog element is the following:

<dialog
        id="bidimailui-dialog"
        xmlns:html="http://www.w3.org/1999/xhtml"
        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
        title="&bidimailpack-settings;"
        dlgbuttons="accept,cancel">

also, if I create a new Thunderbird profile, install the extension, and try opening the preferences dialog - it opens just fine with no complaints.

So, what's going on?

[cleidigh]

@eyalroz hey how's it going each name Space needs to be identified in the dialogue: One of my samples:

<dialog class="options-dialog" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" xmlns:html="http://www.w3.org/1999/xhtml" id="iet-ng-tests-dialog" title="ImportExportNG Tests 0.1.15" type="child">

@cleidigh

Update: clearly I cannot read! . Not sure how I missed you already had it... does your input like:

<html:input id="csvSep" size="1" maxlength="1" />

[cleidigh]

@eyalroz That sounds like me. caching issue start with -purgecaches?

[cleidigh]

@eyalroz For development . I always create a development shortcut with a specific profile and the pc "C:\Program Files (x86)\Mozilla Thunderbird68\thunderbird.exe" -profile "C:\Users\Christopher\AppData\Roaming\Thunderbird\Profiles\testprof68.default" --purgecaches

every once in a while something where happens and I uninstall/reinstall

[eyalroz]

@cleidigh : Can you roll up your answers into a single concise answer?

[cleidigh]

on the -purgecaches ?

[eyalroz]

@cleidigh : On the -purgecaches and the suggestion to run it occasionally/always to avoid caching issues. A link to some more text about why purging caches is ever necessary would also be useful.

[cleidigh]

@eyalroz For that I did finally find something http://kb.mozillazine.org/Command_line_arguments

[eyalroz]

@cleidigh : So, what I'm suggesting is that you delete all of your comments here and replace them with a single comment with the answer; then I'll delete all my comments. Since the conversation will not be interesting to people who find this bug.