FlowTask – simple yet interactive task board for your mobile browser

I check out every simple task board I can find—because eventually every Trello becomes a Jira. That said, I found this one's usage very non-obvious. It wasn't clear to me there are multiple columns. At first I tried to find a checkbox or whatever to complete tasks, which obviously doesn't work because you're expected to drag it to the invisible columns to the right. I only discovered this by accident by dragging a task down and slightly sideways. Scrolling horizontally does not work except by dragging a task. Doing that doesn't move it to the next row except after waiting a very long time if you drag from the right side.