Page 1 of 1

GTK3 Comboboxes unusable on touch display

Posted: Thu Sep 20, 2018 10:26 am
by PeterO
I've discovered that the combobox in GTK3 is unusable on a touch screen like the official 7" display.

First found the problem in my own code then found the combobox demo code in gtk3-demo has the same problems.

gtk3-demo comes from the gtk-3-examples package and can can be install with

Code: Select all

sudo apt-get install gtk-3-examples
I can't find anything other than vague mentions of this problem and no suggestions for solutions.

PeterO

Re: GTK3 Comboboxes unusable on touch display

Posted: Thu Sep 20, 2018 10:43 am
by jamesh
What are the symptoms?

Re: GTK3 Comboboxes unusable on touch display

Posted: Thu Sep 20, 2018 11:53 am
by PeterO
Combobox is unusable.

Install the demo and try it yourself.

The "Items with icons" example won't allow the selection to be changed from "Warning"
With a mouse the selection highlighting follows the mouse pointer, but with the touch screen the selection won't change.

And it is inconsistent too. Once in a while it seems to work for one change, then it stops working again.

PeterO

Re: GTK3 Comboboxes unusable on touch display

Posted: Fri Sep 21, 2018 1:04 pm
by PeterO
Worked around problem using a GtkMenuButton and a GtkPopover, which works nicely :-)
Image
PeterO

Re: GTK3 Comboboxes unusable on touch display

Posted: Fri Sep 21, 2018 8:18 pm
by Paeryn
It could be that GTK+3's combo-box suffers from being too sensitive, clicking it brings the selections up and requires a second click to choose an option. However if the pointer moves so much as 1 pixel (I think, definitely very little movement) whilst that first click happens then it automatically selects whatever is under the pointer on release. With a touchscreen there is a big chance that a small movement is registered between touching and releasing. You might not notice that the list was opened if it hasn't had time to update the display before the selection happens.