We should try to use split buttons for all toolbar color choosers, for a longer rationale, see: bug 45671.
How to get to see the button:
* Open Writer
* Insert a table via Ctrl-F12
/Result/ A table and the table toolbar appear.
* In the toolbar, find the Line Color item (icon: a blue line and a color bucket)
See that the button is a simple button, not a split button.
It is for using mouse cursor as brush?
And why only one icon and not all 4?
(In reply to comment #1)
> It is for using mouse cursor as brush?
> And why only one icon and not all 4?
For every color button on the toolbar that should be changed to a 'split button' a separate bug has been entered. See bug 45671, which is the meta bug for them.
If there is a color button that you do not see in the bug, you ar einvited to enter it as a separate bug and link it to bug 45671. (See this bug as example)
I mean "Border style", "Border color", "Borders" and "Background" on "Table toolbar".
And thanks for improving office usability
Winfried Donkers committed a patch related to this issue.
It has been pushed to "master":
fdo#45682 split button for writer table line color