I tried to change the font by backspacing whatever the default was in the font family box in settings, but once I deleted the last character, the program crashed and would not open again.

Running with a trace gets:

    thread 'main' panicked at 'assertion failed: `(left == right)`
      left: `23`,
     right: `0`', /home/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/font-kit-0.10.1/src/loaders/freetype.rs:817:13
    stack backtrace:
       0: rust_begin_unwind
                 at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/panicking.rs:498:5
       1: core::panicking::panic_fmt
                 at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/core/src/panicking.rs:116:14
       2: core::panicking::assert_failed_inner
       3: core::panicking::assert_failed
       4: font_kit::loaders::freetype::Font::rasterize_glyph
       5: piet_wgpu::pipeline::Cache::get_glyph_pos
       6: piet_wgpu::text::WgpuText::get_glyph_pos
       7: piet_wgpu::text::WgpuTextLayout::rebuild
       8: <piet_wgpu::text::WgpuTextLayoutBuilder as piet::text::TextLayoutBuilder>::build
       9: lapce_core::config::Config::editor_text_width
      10: <lapce_core::terminal::LapceTerminal as druid::widget::widget::Widget<lapce_core::data::LapceTabData>>::layout
      11: druid::core::WidgetPod<T,W>::layout
      12: <lapce_core::scroll::LapcePadding<T,W> as druid::widget::widget::Widget<T>>::layout
      13: druid::core::WidgetPod<T,W>::layout
      14: <lapce_core::terminal::LapceTerminalView as druid::widget::widget::Widget<lapce_core::data::LapceTabData>>::layout
      15: druid::core::WidgetPod<T,W>::layout
      16: <lapce_core::split::LapceSplitNew as druid::widget::widget::Widget<lapce_core::data::LapceTabData>>::layout
      17: druid::core::WidgetPod<T,W>::layout
      18: <lapce_core::terminal::TerminalPanel as druid::widget::widget::Widget<lapce_core::data::LapceTabData>>::layout
      19: druid::core::WidgetPod<T,W>::layout
      20: <lapce_core::tab::LapceTabNew as druid::widget::widget::Widget<lapce_core::data::LapceTabData>>::layout
      21: <druid::widget::lens_wrap::LensWrap<T,U,L,W> as druid::widget::widget::Widget<T>>::layout
      22: druid::core::WidgetPod<T,W>::layout
      23: <lapce_core::window::LapceWindowNew as druid::widget::widget::Widget<lapce_core::data::LapceWindowData>>::layout
      24: <druid::widget::lens_wrap::LensWrap<T,U,L,W> as druid::widget::widget::Widget<T>>::layout
      25: druid::core::WidgetPod<T,W>::layout
      26: druid::window::Window<T>::layout
      27: druid::window::Window<T>::do_paint
      28: druid::win_handler::AppState<T>::paint_winit_window
      29: druid::app::AppLauncher<T>::launch::{{closure}}
      30: winit::platform_impl::platform::x11::EventLoop<T>::run_return::single_iteration
      31: winit::platform_impl::platform::x11::EventLoop<T>::run
      32: winit::platform_impl::platform::EventLoop<T>::run
      33: winit::event_loop::EventLoop<T>::run
      34: lapce_core::app::lanuch
    note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

Agree with other comments here that it's a bit too unusable at the moment, and unfortunately I wasn't even 30 seconds into my demo before this happened, so I can't really comment on the rest of the application.