Proposal: macOS UI improvements and Tcl/Tk compatibility notes

[nholzmann]

Summary

While setting up and testing this app on macOS, I encountered two issues that affect the user experience:

1. Tcl/Tk 9.0 incompatibility - The app crashes with newer Python installations
2. Aqua theme limitations - Button sizing and disabled states don't work correctly

I've submitted PR #90 with dark mode support and window size improvements, but wanted to discuss a more comprehensive fix for the button issues.

Issue 1: Tcl/Tk 9.0 Breaks tkcalendar

Homebrew's latest Python ships with Tcl/Tk 9.0, which causes tkcalendar to fail with:

_tkinter.TclError: bad option "variable": must be add, info, or remove

Workaround: Build Python with Tcl/Tk 8.6 using pyenv:

brew install tcl-tk@8
env LDFLAGS="-L$(brew --prefix tcl-tk@8)/lib" \
    CPPFLAGS="-I$(brew --prefix tcl-tk@8)/include" \
    PKG_CONFIG_PATH="$(brew --prefix tcl-tk@8)/lib/pkgconfig" \
    PYTHON_CONFIGURE_OPTS="--with-tcl-tk-includes='-I$(brew --prefix tcl-tk@8)/include' --with-tcl-tk-libs='-L$(brew --prefix tcl-tk@8)/lib -ltcl8.6 -ltk8.6'" \
    pyenv install 3.12.8

This might be worth noting in the README for macOS users.

Issue 2: Aqua Theme Limitations

The native macOS aqua ttk theme has significant limitations:

Issue	Description
No button height control	Padding, height, and image techniques are ignored. Multi-line button text gets clipped.
Disabled states invisible	No visual distinction between enabled/disabled buttons
Styling ignored	Most ttk.Style.configure() options have no effect

Proposed fix: Switch to the alt theme on macOS:

if sys.platform == 'darwin':
    style.theme_use('alt')

Trade-offs

Aspect	Aqua (current)	Alt (proposed)
Native macOS look	✅ Yes	❌ No
Button height control	❌ No	✅ Yes
Disabled state visibility	❌ Poor	✅ Good
Dark mode auto-adapt	✅ Yes	❌ Needs manual colors
Respects styling	❌ No	✅ Yes

The dark mode colors can be handled manually (already implemented in PR #90's ThemeColors class).

Question

Would you be open to a follow-up PR that:

1. Switches macOS to the alt theme for proper button behavior
2. Adds a README note about Tcl/Tk 8.6 requirement for macOS

Happy to implement if there's interest!