Hot answers tagged software
Ktimetracker Although I have no experience with this particular software, it might suit your needs. It's from KDE, so if you are using other Desktop Environment it might install a lot of dependencies. https://www.kde.org/applications/utilities/ktimetracker/
I use Hamster. It meets all your requirements. I have mine set to track to the nearest 1/10 of an hour (6 minutes). If there is inactivity for that period, it stops tracking but also every 6 minutes a 5-second tiny window pops up in the corner to remind you as to which project you're currently tracking against...to included you're currently not tracking ...
https://pomotodo.com/ From the above: "Your todolist and Pomodoro records stay updated across all your devices. You can use Pomotodo anywhere and anytime you want, even offline!" "Contains full workflow management. Collect ideas, schedule works, finish tasks and review history right in the app." 'nuff said.
I think cherrytree might be what you are looking for. http://www.giuspen.com/cherrytree/ You can insert check-boxes (Edit->Insert special character) and tick them or untick them with a click. http://www.giuspen.com/topic/cherrytree-on-mac-osx/ The image is from Linux, but it's also available for Windows. I don't see it for OSX, but somebody got it ...
Check out this article. It lists 5 different ways to use GT from your desktop, which, I believe, includes what you're seeking. http://www.makeuseof.com/tag/five-killer-ways-to-use-google-tasks/
I like kanbanflow. It combines a kanban style to do list with the pomodoro method. I run it on my work computer through Chrome, and it has an Android and Iphone versions too.
Only top voted, non community-wiki answers of a minimum length are eligible