The field now owns the keyboard; what it does not yet own is the characters

Measured, not reasoned. A per-frame trace of the ImGui state is what finally named the mechanism,
and it is a deadlock, not a focus problem:

  [UX] frame want_text=0 want_kb=0 active=0 buf=158.74   <- frame 1: the widget is not active yet
  [UX] frame want_text=0 want_kb=0 active=1 buf=158.74   <- frame 2: now it is
  (nothing further)                                       <- and the canvas stops

This canvas repaints ON DEMAND. ImGui decides whether it wants the keyboard at the END of a frame,
from the active item; GLCanvas3D::on_char only calls render() when update_key_data() says ImGui
wants it. So: no frames -> WantTextInput never turns on -> no render on a keystroke -> still no
frames. The characters sit in ImGui's input queue and the field is exactly as deaf as the window
it replaced, for a completely different reason.

request_frame breaks the circle, and the same trace says so:

  [UX] frame want_text=1 want_kb=1 active=1

That is the first time in this file's history that the value field has owned the keyboard without
asking a window manager for it.

STILL OPEN: the typed characters do not reach the buffer (buf stays at the prefill) and the frames
stop after nine. The pump is the suspect — on software GL request_repaint() calls m_canvas->render()
SYNCHRONOUSLY, so this asks for a render from inside a render; it needs to schedule one instead.
That is the next thing to measure, not to guess.

The deployed binary on behemoth is restored to 00d6c191dc (md5 0eeb9a58cef5), byte-identical to
the last good build. Nothing from this branch is installed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011FbJKJAJxxkhDTs9XdZzKA

src/slic3r/GUI/CAD/DesignCanvas.cpp

@@ -87,6 +87,7 @@ DesignCanvas::DesignCanvas(wxWindow* parent)
     // The tool draws it: it owns the frame's ImGui pass and the render scale. Handing it a raw
     // pointer rather than the unique_ptr keeps the ownership where it was.
     m_sketch_tool.inline_editor = m_inline_editor.get();
+    m_inline_editor->request_frame = [this] { request_repaint(); };
     m_sketch_tool.on_inline_edit = [this](wxPoint screen_px, double current,
                                           const std::string& title,
                                           std::function<void(double)> commit,