Tagging preset: value_template does not update value, right away, with conditions

[skyper]

Sorry, simon04. I really love this feature but it still not working properly. Thanks for your work.

What steps will reproduce the problem?

1. Have a condition in the expression for value_template="" like the one in #20842.
2. Have a relation selected matching the preset with some of the tags already tagged
3. Open the preset, change a tag which is used in the expression with a condition, like route=*.

    <group name="Public Transport" icon="presets/transport/bus.svg">
        <item name="Public Transport Route (Rail)" icon="presets/misc/route.svg" type="relation" preset_name_label="true">
            <link wiki="Public_transport#Service_routes" />
            <space />
            <key key="type" value="route" />
            <combo key="route" text="Route type" values="train,subway,monorail,tram,light_rail" values_searchable="true" match="keyvalue!" />
            <key key="public_transport:version" value="2" /> <!-- only validate marked relations in order to avoid false positives -->
            <text key="name" text="Name" value_template="?{route=train 'Train'|route=subway 'Subway'|route=monorail 'Monorail'|route=tram 'Tram'|route=light_rail 'Light_rail'|''} {ref}?{': {from} - {via} - {to}'|': {from} - {to}'|''}" />
            <text key="ref" text="Reference" />
            <text key="from" text="from" />
            <text key="to" text="to" />
            <text key="via" text="Via" />
        </item> <!-- Public Transport Route (Rail) -->

What is the expected result?

The value is adjusted right away, after changing any tag which is used in the expression.

What happens instead?

The value might be adjusted when closing the dialog with "ok" but not always

Please provide any additional information below. Attach a screenshot if possible.

It work with tags not part of a condition, like ref=*.
Opening the preset after closing changes the value again to the correct content.
The expression, especially conditions, are not always evaluated after changing an involved tag.

One more question: Is it wise to change an existing value, automatically, without user's interaction?
Think we need at least a preference option to enable/disable this feature of overwriting values.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2021-05-04 21:01:14 +0200 (Tue, 04 May 2021)
Revision:17860
Build-Date:2021-05-05 01:30:58
URL:https://josm.openstreetmap.de/svn/trunk

Plugins:
+ tagging-preset-tester (35640)

Tagging presets:
+ ${HOME}/JOSM/new/resources/data/defaultpresets_17833_route_17661_18662.xml