When you select the line from the panel, if you Alt+Click (or the Mac equivalent) instead of just clicking, the line will be entered as a system object and will behave just like system text (e.g., tempo marks, etc.).
When you select the line from the panel, if you Alt+Click (or the Mac equivalent) instead of just clicking, the line will be entered as a system object and will behave just like system text (e.g., tempo marks, etc.).