I can also confirm that this is happening.

To replicate:
1. In the staff interface, go to the details page for a record with items.
2. Click on the 'Items' tab.
3. For an item, change 'Bookable' to 'Yes' and click on 'Update'.
4. Go back to the normal tab for the record.
5. Click on the "Place booking" button.
6. Select a patron for the patron field.
7. Click in the period field.
8. Note that if you select a date (single click as normal for a date field), and then try to press the "Submit" button, the period field is blank.
9. Click on the period field again, then double click a date - this time it remains, and you can click the "Submit" button.

You are picking a start AND an end date.. it's not a double click.. it's a start (click one date) then end (click another date).

Katrin suggests a hint should be added to clarify this.

Yes, because we didn't get it :D

Honestly.. I'm not sure where to put a hint or what to write in it...

To me 'Period' means 'Two dates.. start and end'... and the visual queues are also clear in the picker.

Created attachment 160857 [details]
Picker open

It was not obvious to me.

However, it seems obvious now that you've pointed it out!

I don't think I've seen this pattern elsewhere in Koha (but I'm probably wrong about that...).

Since I'm not familiar with the booking feature, I "assumed" it was just for one day. Normally, with the date picker, I pick a day then click outside the picker so that the date appears in the input field.

So I hope that this didn't come across as too negative!

Some ideas - not tied to any of them:

1. Label for Period: 
   . Start and end date of booking (this is quite long though)
   . Booking dates
   . Start and end date

2. Hint for the field (like for the patron):
   . Select the booking start and end date

3. Not sure how these would work for translation.

I think I prefer a combination of "Booking dates" as the label and a hint for the field "Select the booking start and end date".

Other things noted (outside scope for this bug, just noting - happy to open bugs if they don't exist already):

1. Not sure how to use the 'Tomorrow' date link in the picker - does nothing for me. Should this be disabled?

2. Accessibility things - using keyboard instead of a mouse (I don't know enough to know if these are fixable, or even issues):
   . Patron field: works OK with tab, search, and then the down arrow to select a patron
   . Item field: can tab to it, but can't select item using down or up arrows
   . Period: tab opens date picker, but not sure how to select a date range

3. You need to pick a date range: what if you only wanted to book for one day?

Created attachment 162266 [details] [review]
Bug 35532: Update date select field and add hint

This patch updates the 'Period' select from 'Period' to 'Booking dates'
and adds a hint beneath it too.

Created attachment 162267 [details] [review]
Bug 35532: Remove shortcut buttons from flatpickr

It doesn't make sense to have the shortcut buttons in the range picker
for bookings. This patch adds the ability to remove them entirely from
display and uses that option in the bookings modal.

Created attachment 162274 [details] [review]
Bug 35532: Update date select field and add hint

This patch updates the 'Period' select from 'Period' to 'Booking dates'
and adds a hint beneath it too.

Signed-off-by: David Nind <david@davidnind.com>

Created attachment 162275 [details] [review]
Bug 35532: Remove shortcut buttons from flatpickr

It doesn't make sense to have the shortcut buttons in the range picker
for bookings. This patch adds the ability to remove them entirely from
display and uses that option in the bookings modal.

Signed-off-by: David Nind <david@davidnind.com>

Thanks Martin!

Created attachment 162844 [details] [review]
Bug 35532: Update date select field and add hint

This patch updates the 'Period' select from 'Period' to 'Booking dates'
and adds a hint beneath it too.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>

Created attachment 162845 [details] [review]
Bug 35532: Remove shortcut buttons from flatpickr

It doesn't make sense to have the shortcut buttons in the range picker
for bookings. This patch adds the ability to remove them entirely from
display and uses that option in the bookings modal.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>

Even I couldn't miss it now, thanks :)

Pushed for 24.05!

Well done everyone, thank you!

Depends on Bug 35426 not in 23.11.x

(In reply to Fridolin Somers from comment #16)
> Depends on Bug 35426 not in 23.11.x

Maye worth reconsidering - a lot of us didn't understand this new type of date selector and this improves things quite a bit.

(In reply to Katrin Fischer from comment #17)
> (In reply to Fridolin Somers from comment #16)
> > Depends on Bug 35426 not in 23.11.x
> 
> Maye worth reconsidering - a lot of us didn't understand this new type of
> date selector and this improves things quite a bit.

If needed for 23.11.x please provide new patches

Pushed to 23.11.x for 23.11.04

(In reply to Fridolin Somers from comment #18)
> (In reply to Katrin Fischer from comment #17)
> > (In reply to Fridolin Somers from comment #16)
> > > Depends on Bug 35426 not in 23.11.x
> > 
> > Maye worth reconsidering - a lot of us didn't understand this new type of
> > date selector and this improves things quite a bit.
> 
> If needed for 23.11.x please provide new patches

No need, I understood the conflict.
Now calendar.inc is identical between 23.11.x and master

Missing 23.05.x dependencies, no backport.