Bookmarks - too much data to load

[kocio]

This is a more general version of #15148. While the fix was enough to work with my home location or a ​Smalltown, there are many places where it fails.

What steps will reproduce the problem?

Try to open Berlin by searching its name in Nominatim.

What is the expected result?

Berlin data should be downloaded and probably visible in the edit window (see also #15238).

What happens instead?

The data are not downloaded, since there's too much data.

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: 2017-09-02 14:47:18 +0200 (Sat, 02 Sep 2017)
Build-Date:2017-09-02 20:53:16
Revision:12712
Relative:URL: ^/trunk

Identification: JOSM/1.5 (12712 pl) Linux Ubuntu 17.04
Memory Usage: 279 MB / 1707 MB (77 MB allocated, but free)
Java version: 1.8.0_131-8u131-b11-2ubuntu1.17.04.3-b11, Oracle Corporation, OpenJDK 64-Bit Server VM
Screen: :0.0 1366x768
Maximum Screen Size: 1366x768
Java package: openjdk-8-jre:amd64-8u131-b11-2ubuntu1.17.04.3
WebStart package: icedtea-netx:amd64-1.6.2-3.1ubuntu3
Java ATK Wrapper package: libatk-wrapper-java:all-0.33.3-13
VM arguments: [-Dicedtea-web.bin.name=javaws, -Dicedtea-web.bin.location=/usr/bin/javaws, -Djava.security.manager, -Djava.security.policy=/etc/icedtea-web/javaws.policy]
Dataset consistency test: No problems found

Plugins:
+ OpeningHoursEditor (33185)
+ Tracer2 (33004)
+ buildings_tools (33004)
+ continuosDownload (53)
+ tagging-preset-tester (33004)
+ utilsplugin2 (33579)

Last errors/warnings:
- E: org.openstreetmap.josm.plugins.PluginListParseException: Nie udało się utworzyć informacji z pliku manifest wtyczki „mbtiles.jar”. Przyczyna: org.openstreetmap.josm.plugins.PluginException: Wystąpił błąd we wtyczce mbtiles. Przyczyna: java.io.IOException: invalid manifest format
- W: Unable to initialize OpeningHourTest because no JavaScript engine has been found
- W: Unable to initialize OpeningHourTest because no JavaScript engine has been found

[Don-vip]

Berlin data should be downloaded

We cannot download all Berlin data. So which part of Berlin should be downloaded? JOSM cannot guess where exactly in Berlin you want to edit. I'd say it's up to you, for big cities, to switch to first tab and narrow your download area.

Or even simpler: perform a better search. If I search for "Alexanderplatz, Berlin", I have no problem.

[kocio]

Why not make the download zoom level even higher than z15?

I may not know the streets in New York and if I look for a NY, it probably means I can navigate there or make next search more precise if I want. It's easier to get too few data and zoom out than get nothing at all and try to find smaller place outside the download window.