Fix wxChoice/wxComboBox dropdown rendering and add tests

- Fix empty clip region bug in wx.js clipRect function
- Add dropdown mouse interaction tests
- Add *.log to gitignore
- Make build script clean by default (use --no-clean to skip)
- Add wxGLCanvas canvas element fix documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.gitignore

@@ -39,3 +39,4 @@ wxwidgets-clean/
 /tests/wasm-app/*.js
 /tests/wasm-app/minimal_test.wasm
 /temp/
+*.log

docs/06-WXGLCANVAS-CANVAS-ELEMENT-FIX.md

@@ -0,0 +1,146 @@
+# 06 - wxGLCanvas WASM Canvas Element Integration
+
+This document describes how to fix wxGLCanvas to render visibly in WASM by creating its own canvas element.
+
+## Problem
+
+wxGLCanvas currently hardcodes `m_canvasTarget = "#canvas"` which creates WebGL context on the main wxUniversal 2D canvas, causing a conflict. The GL rendering doesn't appear because it's overwritten by 2D UI rendering.
+
+## Key Discovery
+
+The WASM port already supports **multiple canvas elements per window**:
+- Main window uses `#canvas` for 2D rendering
+- Child windows can each get their own canvas element via `createWindow(id, needsCanvas=true)`
+- Windows are positioned absolutely with z-index layering
+- JavaScript (wx.js) manages canvas creation, positioning, and context stacking
+
+## How KiCad Uses wxGLCanvas
+
+```
+wxFrame (EDA_DRAW_FRAME)
+  └── EDA_DRAW_PANEL_GAL (wxScrolledCanvas)
+         └── OPENGL_GAL (inherits from wxGLCanvas)
+              - Sized to match parent
+              - Child window positioned within parent
+              - Has its own GL context
+```
+
+Key KiCad files:
+- `kicad/common/gal/opengl/opengl_gal.cpp` - GL rendering implementation
+- `kicad/common/draw_panel_gal.cpp` - Creates OPENGL_GAL as child: `new OPENGL_GAL(..., this, ...)`
+- `kicad/include/gal/hidpi_gl_canvas.h` - wxGLCanvas wrapper class
+
+---
+
+## Solution
+
+wxGLCanvas should integrate with the existing WASM window system:
+
+1. **Create its own canvas element** - Use `createWindow(id, needsCanvas=true)` in JavaScript
+2. **Create WebGL context on that canvas** - Use selector `#window-{id} canvas`
+3. **Handle positioning via window system** - `setWindowRect()` positions the canvas
+
+### Key JavaScript Functions (already exist in wx.js)
+
+```javascript
+createWindow(id, needsCanvas, isVisible, classList)
+setWindowRect(id, x, y, width, height)
+setWindowVisibility(id, isVisible)
+destroyWindow(id)
+```
+
+---
+
+## Implementation
+
+### Step 1: Modify Create() to create canvas element
+
+In `wxwidgets/src/wasm/glcanvas.cpp`:
+
+```cpp
+bool wxGLCanvas::Create(wxWindow *parent, ...)
+{
+    if ( !wxWindow::Create(parent, id, pos, size, style, name) )
+        return false;
+
+    // Create a window with canvas element in JavaScript
+    int cssId = GetCSSId();
+    EM_ASM({
+        createWindow($0, true, true, "glcanvas");
+    }, cssId);
+
+    // Position the canvas
+    wxPoint screenPos = GetScreenPosition();
+    wxSize clientSize = GetClientSize();
+    EM_ASM({
+        setWindowRect($0, $1, $2, $3, $4);
+    }, cssId, screenPos.x, screenPos.y, clientSize.GetWidth(), clientSize.GetHeight());
+
+    // Set dynamic canvas selector
+    m_canvasTarget = wxString::Format("#window-%d canvas", cssId).ToStdString();
+
+    return CreateWebGLContext(dispAttrs);
+}
+```
+
+### Step 2: Override DoSetSize for resize handling
+
+```cpp
+void wxGLCanvas::DoSetSize(int x, int y, int width, int height, int sizeFlags)
+{
+    wxWindow::DoSetSize(x, y, width, height, sizeFlags);
+
+    wxPoint screenPos = GetScreenPosition();
+    wxSize clientSize = GetClientSize();
+    EM_ASM({
+        setWindowRect($0, $1, $2, $3, $4);
+    }, GetCSSId(), screenPos.x, screenPos.y, clientSize.GetWidth(), clientSize.GetHeight());
+}
+```
+
+### Step 3: Handle visibility
+
+```cpp
+void wxGLCanvas::DoShow(bool show)
+{
+    wxWindow::DoShow(show);
+    EM_ASM({
+        setWindowVisibility($0, $1);
+    }, GetCSSId(), show);
+}
+```
+
+### Step 4: Clean up in destructor
+
+```cpp
+wxGLCanvas::~wxGLCanvas()
+{
+    if ( m_webglContext > 0 )
+    {
+        emscripten_webgl_destroy_context(m_webglContext);
+        m_webglContext = 0;
+    }
+    EM_ASM({
+        destroyWindow($0);
+    }, GetCSSId());
+}
+```
+
+---
+
+## Files to Modify
+
+| File | Changes |
+|------|---------|
+| `wxwidgets/src/wasm/glcanvas.cpp` | Main implementation - create own canvas, dynamic selector, resize/visibility handling |
+| `wxwidgets/include/wx/wasm/glcanvas.h` | Add DoSetSize, DoShow declarations if needed |
+
+---
+
+## Testing
+
+The existing test app in `tests/wasm-app/` with the OpenGL tab will verify:
+1. Canvas element is created in DOM
+2. WebGL context is on the correct canvas
+3. GL rendering appears in the canvas area
+4. Legacy GL emulation works (via `-sLEGACY_GL_EMULATION`)

scripts/build-wxuniversal-wasm.sh

@@ -12,8 +12,8 @@
 #     ghcr.io/vslavik/bakefile:0.2 bakefile_gen
 #
 # Usage:
-#   ./build-wxuniversal-wasm.sh           # Build (incremental)
+#   ./build-wxuniversal-wasm.sh              # Clean build (default)
-#   ./build-wxuniversal-wasm.sh --clean   # Clean build
+#   ./build-wxuniversal-wasm.sh --no-clean   # Incremental build
 
 set -e
 
@@ -40,9 +40,9 @@ if [ "$WX_SOURCE/configure.in" -nt "$WX_SOURCE/configure" ]; then
     (cd "$WX_SOURCE" && autoconf)
 fi
 
-# Clean if requested
+# Clean by default, unless --no-clean is passed
-if [ "$1" = "--clean" ]; then
+if [ "$1" != "--no-clean" ]; then
-    echo "Cleaning build directory..."
+    echo "Cleaning build directory (use --no-clean to skip)..."
     rm -rf "$BUILD_DIR"
 fi
 

tests/e2e/wxwidgets.spec.ts

@@ -194,6 +194,58 @@ test.describe('wxWidgets WASM - Diagnostics', () => {
 
     await page.screenshot({ path: 'test-results/10-lists-clicked.png', fullPage: true });
 
+    // Test wxChoice dropdown - the Choice control is to the right of the ListBox
+    console.log('--- Testing wxChoice Dropdown ---');
+
+    // Debug: Check all window divs in the DOM before clicking
+    const windowsBefore = await page.evaluate(() => {
+      const windows = document.querySelectorAll('[id^="window-"]');
+      return Array.from(windows).map(w => ({
+        id: w.id,
+        display: (w as HTMLElement).style.display,
+        rect: w.getBoundingClientRect()
+      }));
+    });
+    console.log('Windows before click:', JSON.stringify(windowsBefore));
+
+    // Click on the wxChoice dropdown button (approximately right side of the panel)
+    // The Choice section is in a separate box to the right, starts around x=640
+    // The wxChoice dropdown button (arrow) is at approximately x=800
+    await page.mouse.click(box.x + 800, box.y + 100);
+    await page.waitForTimeout(500);
+
+    // Debug: Check all window divs in the DOM after clicking
+    const windowsAfter = await page.evaluate(() => {
+      const windows = document.querySelectorAll('[id^="window-"]');
+      return Array.from(windows).map(w => ({
+        id: w.id,
+        display: (w as HTMLElement).style.display,
+        width: (w as HTMLElement).style.width,
+        height: (w as HTMLElement).style.height,
+        rect: w.getBoundingClientRect()
+      }));
+    });
+    console.log('Windows after click:', JSON.stringify(windowsAfter));
+
+    await page.screenshot({ path: 'test-results/10a-choice-dropdown-open.png', fullPage: true });
+
+    // Click on the second option in the dropdown (should be "Green")
+    // Dropdown appears below the wxChoice, options are around x=700-800
+    await page.mouse.click(box.x + 700, box.y + 140);
+    await page.waitForTimeout(300);
+
+    await page.screenshot({ path: 'test-results/10b-choice-selected.png', fullPage: true });
+
+    // Try opening the dropdown again to verify it works
+    await page.mouse.click(box.x + 800, box.y + 100);
+    await page.waitForTimeout(500);
+
+    await page.screenshot({ path: 'test-results/10c-choice-dropdown-reopen.png', fullPage: true });
+
+    // Click elsewhere to close
+    await page.mouse.click(box.x + 200, box.y + 300);
+    await page.waitForTimeout(300);
+
     // === TAB 5: OpenGL ===
     console.log('--- Testing OpenGL Tab ---');
 

wxwidgets

@@ -1 +1 @@
-Subproject commit 54beb85efd41ac98c14b810895e69784c948bbae
+Subproject commit 2b32d5bfab8c4864b7eef5b06c14693375ee919a