Tkinter Optionmenu Too Narrow on Mac

[zjdavid]

BPO	42977
Nosy	@terryjreedy, @serhiy-storchaka, @E-Paine, @zjdavid
Files	TKinter Menu issue.png: Screenshot of the issue

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-01-24.12:18:36.585>
created_at = <Date 2021-01-20.14:48:54.306>
labels = ['type-bug', 'expert-tkinter', '3.9']
title = 'Tkinter Optionmenu Too Narrow on Mac'
updated_at = <Date 2021-01-25.03:57:26.542>
user = 'https://github.com/zjdavid'

bugs.python.org fields:

activity = <Date 2021-01-25.03:57:26.542>
actor = 'zjdavid'
assignee = 'none'
closed = True
closed_date = <Date 2021-01-24.12:18:36.585>
closer = 'serhiy.storchaka'
components = ['Tkinter']
creation = <Date 2021-01-20.14:48:54.306>
creator = 'zjdavid'
dependencies = []
files = ['49752']
hgrepos = []
issue_num = 42977
keywords = []
message_count = 5.0
messages = ['385345', '385426', '385555', '385578', '385600']
nosy_count = 4.0
nosy_names = ['terry.reedy', 'serhiy.storchaka', 'epaine', 'zjdavid']
pr_nums = []
priority = 'normal'
resolution = 'third party'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue42977'
versions = ['Python 3.9']

[zjdavid]

Hello,

I am building a program with Tkinter. However, I found the Optionmenu widget has inconsistent behaviors on default lengths on a Mac and a Windows PC.

So I set the width of an optionmenu through menu.configure(width=70). On Windows, this correctly sets the menu width to 70 when the program runs. However, on a Mac, the menu is still very narrow at the start. It only expands to 70 after I select an option.

I have attached a screenshot to help explain the issue. It does not occur on Windows.

[E-Paine]

I suspect this is just a MacOS behaviour, if not then it is a Tk bug. If you really need to enforce the width, you could tell it to expand horizontally in the layout. An example of this would be as follows:

tk.Frame(root, height=1, width=300).pack()
tk.OptionMenu(root, tk.StringVar(), "test").pack(fill="x")

A bit more detail on the Tk side of things:
tkinter doesn't actually use tk_optionMenu and instead creates its own menubutton and menu. The issue with the menubutton width not changing also exists when working directly with Tk (pack [menubutton .p -width 100]). However, the same behaviour can be shown when using tk_optionMenu, so changing tkinter to use that instead would not fix this issue.

[terryjreedy]

This should likely be closed as 3rd party

zjdavid Which python release, which macOS, which installer, which tk patchlevel? (IDLE Help=>About displays it).

At least one of the 3.9.1 python.org mac installers installs 8.6.10. We cannot be responsible for problems fixed in this release.

[serhiy-storchaka]

I concur with E. Paine that you should use pack(fill="x") if you want to stretch a widget. And in any case Tkinter itself does not manage layout, it is just a wrapper around Tk, so if you think that the default layout of a button is wrong on some platforms, you should report it to the Tk team.

[zjdavid]

Thanks for your help! I agree that it is probably a Tk issue. I will contact them and back with more information.