I wasn't completely happy with the execution icons introduced in 1.9.16 because I feel their function is not immediately clear to the user. So you need to hover to see what they actually do from the tooltip.
I have created a set of icons based on icons available from [url]materialdesignicons.com[/url] I feel are more clear. I've used the same color scheme indicated to use the status in the execution treeview to make this feel consistent.
I've made them available on https://github.com/MichielVT/testlink-c ... ionButtons
I can make the svg files available if you would like to change them further.
Let me know what you think about these.