Is the Inspector Bar visible before you hit the <Tab> key?
If not, then you have to make its Toolbar visible (right-click outside the Model or Paper space, then select the Toolbars tab).
Is so, then which function(s) have you selected that is failing to work as expected?
TC Pro Platinum 2019, 2018, 2017, 2016 & 2015 (all with LightWorks & RedSDK) & 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