Under the Format drop-down menu, you can adjust the 'stacking' of objects.
Any object can be sent to the Back or Front or Forward One or Backward One.
If that doesn't work, there are other things to do, but try this first.
TC Pro Platinum 2017, 2016 & 2015 (all with LightWorks) & V21
System: i7-5820K @ 3.30GHz, ASRock X99 Extreme4, 16GB DDR4-2133 RAM, Gigabyte GTX 970, Samsung NVMe SSD 950 (256GB), Windows 7 Pro (64-bit) SP1