为什么将目标属性设置为“_top”或“_parent”会在新选项卡中打开

I've set the following links (found on DEMO) to open in the same tab by using the "_top" target (tried "_parent" as well, but for some reason they keep opening in a new tab. I've tried different browsers, and different devices but it still happens.I've set the following links (found on DEMO) to