They aren’t disabled, as you have seen. They are displayed in grey because they do not belong to the selected month but the one before or the next month. They can still be clicked on, but to get actually selected the date picker needs to switch to the matching month. When November is shown, only days in November can be displayed as selected (i.e. with a grey background), so when you click on a day in late October or early December the date picker duly switches to that month so it can display the new selected date.
The clickable areas are a little larger than the tiny triangles and the dot, thankfully. Where’s the problem? Why would anyone click there if they don’t intend to hit one of those buttons?
Because they offer another way to change months. It be difficult for some users to understand that the only way to change months is to click on days for the next/previous months.
If you need to, you should create a dual selection option (type the date and show the calendar) just as the Set Date Time on the macOS works. This was mentioned in a previous thread:
Yeah, I think it is a waste of time agonising over the peculiarities of the DateTimePicker controls. Their use is pretty straightforward and by combining the two variants (graphical and textual) one has all bases covered. This way selecting some arbitrary date in the far future or past is just as fast and easy as selecting one near the current date.
That is an idea, but it is infortunate that we cannot use the nice graphics display mode.
I unchecked that property, and will let it as is for sometimes to see how I feel about that mode.
I think the suggestion was to use both the graphical and the textual display in parallel. It is easy to synchronise the two and it gives you the best of both worlds.