As for what CPL Leeds said, it's Left ALT + Left Shift + H.
As for what SPC Donohoe Gaudet said, the MicroDAGR is almost as effective for tracking squad movements as STHud. It even displays team colors. When you have it open on the side pressing LCTRL + LSHIFT + Page Up (Page Down) will zoom in and out.
As for what SSG Shundo said, that's the best we can give you on a technical side. However, be aware that there has been some issues with STHud lately on the server side. Usually I only see this if we had a recent change to the Modpack or if we ran an official fun op. Nothing can be done about that other than just using your MicroDAGR instead.