Some WMS template parameters not supported in tracer plugin

[slodki]

What steps will reproduce the problem?

1. Add new server definition to JOSM imagery and tracer2 plugin as: "wms:http://www.w3.org/none?proj={proj}&box={w},{s},{e},{n}&bbox={bbox}"
2. Run sniffer to see HTTP requests made
3. Add imagery layer to JOSM
4. Run tracer2

What is the expected result?

HTTP requests should be made to ​http://www.w3.org/none?proj=EPSG:4326&box=19.9387785,50.0501896,50.0529393,19.9415282&bbox=19.9387785,50.0501896,19.9415282,50.0529393 - all parameters expanded as described at https://josm.openstreetmap.de/wiki/Maps#Documentation

What happens instead?

JOSM generates HTTP requests as expected.
Tracer2 doesn't support {proj} and {n}{w}{s}{e} parameters, generating requests for ​http://www.w3.org/none?proj=%7Bproj%7D&box=%7Bw%7D,%7Bs%7D,%7Be%7D,%7Bn%7D&bbox=19.9344,50.0536,19.9348,50.0540

Online documentation at ​https://wiki.openstreetmap.org/wiki/JOSM/Plugins/Tracer2#Settings suggest all parameters form JOSM imagery are supported: "Address: wms layer address - can be imported from the wms / tms background layer settings in JOSM"

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

URL:http://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2016-01-06 17:30:31 +0100 (Wed, 06 Jan 2016)
Build-Date:2016-01-06 16:32:31
Revision:9329
Relative:URL: ^/trunk

Identification: JOSM/1.5 (9329 pl) Windows 8.1 64-Bit
Memory Usage: 418 MB / 910 MB (146 MB allocated, but free)
Java version: 1.8.0_73, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Dataset consistency test: No problems found