v3.15.0

New features and enhancements

• Introduce ui.popup, a menu on desktop and a dialog on small screens (#1125, #2149, #5613 by @DelScipio, @adosikas, @evnchn, @phifuh, @falkoschindler)
• Make the start method of the run.cpu_bound process pool configurable via run.process_pool_start_method (#6117 by @evnchn, @NiklasNeugebauer, @falkoschindler)
• Speed up binding cleanup with a reverse index (#6135, #6150 by @ftilde, @jwinpbe, @evnchn, @falkoschindler)
• Speed up observable change handlers by resolving expects_arguments once at registration (#6098, #6108 by @maybites, @evnchn, @falkoschindler)
• Add element identity to the "parent slot has been deleted" error (#6153 by @pascalzauberzeug, @evnchn, @falkoschindler)

Bugfixes

• Fix ObservableCollection leaking change handlers and keeping discarded containers alive (#6139, #6140 by @falkoschindler, @evnchn)

• Raise KeyError from ObservableDict.pop() for a missing key, like dict.pop (#6163, #6164 by @evnchn, @falkoschindler)

  Breaking change: app.storage.general, .user, .tab and .client are ObservableDicts, so storage.pop('missing') now raises a KeyError instead of returning None. Pass an explicit default to keep the previous behavior: storage.pop('missing', None).

• Skip change events for no-op mutations of observable collections (#6169, #6171 by @falkoschindler, @evnchn)

• Fix ui.page_title, ui.add_head_html, ui.add_body_html and ui.add_css being lost in async ui.sub_pages builders (#6058, #6147, #6148, #6168 by @cervelas, @evnchn, @falkoschindler)

• Fix run.cpu_bound hanging with the forkserver start method, e.g. on Python 3.14 + Linux (#6166, #6167 by @evnchn, @falkoschindler)

• Fix PermissionError on Windows when clearing storage while a backup is in flight (#6158, #6159, #6173, #6174 by @Jepson2k, @evnchn, @falkoschindler)

• Fix sporadic HTTP 500 when user storage is pruned during an in-flight request (#6145, #6146 by @evnchn, @falkoschindler)

• Fix TypeError in ui.input's shadow text when the autocomplete list is absent (#6161, #6162 by @Jepson2k, @evnchn, @falkoschindler)

• Fix placement and order of ui.fab_actions under dir="rtl" (#6165, #6172 by @roximn148, @evnchn, @falkoschindler)

• Fix crash when loading an STL model into ui.scene with wireframe=True (#5989, #6118, #6137 by @fabian0702, @Jepson2k, @evnchn, @falkoschindler)

• Close streamed media file handles synchronously on teardown (#6149 by @evnchn, @falkoschindler)

Documentation

• Add an accessibility heading tree to the homepage (#6155 by @evnchn, @falkoschindler)

Testing

• Make CPython-only-semantics tests PyPy-compatible (#6157 by @evnchn, @falkoschindler)

Dependencies

• Update nicegui-highcharts to 3.3, fixing dynamic adding and removing of chart series (#6138 by @falkoschindler, @evnchn)

Infrastructure

• Run examples/pytests in CI so bundled example tests can't silently rot (#6141, #6144 by @falkoschindler, @evnchn)

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