Bug 417471

In kmail there are two great features ; you can configure the columns shown to display an icon for important messages, as well as an icon for the TODO tag.

Also, when you click those icons, you simply toggle the important/not important state, or the TODO/DONE one.
When the important state is used, the mail text color is shown in red.
When the TODO tag is used, the mail text color is shown in green.

This is great, and allow an efficient workflow.


But that workflow could be improved with a small addition :
When you receive some mails, you often have a choice to make :
- The mail is basic information -> Read it directly and be done with it
- The mail contains information you need to act on -> Read it and set the TODO tag (so you get a nice color you can identify easily while browsing your previous mails to search for unfinished todos)
- The mail contains information that you worked on, then replied to with a question of your own. -> Now, since some people are unreliable and may miss your email, you WILL need to check later if you got an answer. To do that you need to mark that initial email as "Check back later" (which could color the text in pink for instance).
This way you know you _already have done the work_, but only need to ping again the person you answered to.

This "Check back later" tag (name to be defined) is different than the "TODO" one since a todo means some amount of work have to be done (and that take time), while "Check back later" only needs you to resend a quick message like "Hey, I haven't heard about you on this subject. Could you please get back to me whenever you're available? xoxoxo".

This would go a long way to improve a mail management workflow, and be sure to not miss anything (this is loosely based on the Get Things Done methodology).


Bonus :
Even better, when adding a 'check back later' tag to an email, it could automatically create a task (like you can already do) and just asks for the date and hour, the default calendar being configured somewhere else.
Right now once you created a task from kmail, you have no indication if a particular email has tasks attached to it, or even if those tasks are done.

So the main purpose of this wish is to have a way to color an email with a one click toggle like the TODO one.

Regards