How to reproduce:
1. Open any (empty) Unity Project (2018.3 or newer) and under Player Settings / Other make sure Color Space to Linear
2. Open the Memory Profiler (Window->Analysis->Memory Profiler)
3. Load in the user attached snapshot "Snapshot-637297360362316477.snap"
5. Open the snapshot and to to the Memory Map view
6. Set the Row Size to 16 MB
7. a) Inspect the memory map, find the Native Object highlighted in the screenshots, Display Filters > Native Objects on and off

Actual result: The Native Object is far bigger than the allocation it starts in, coloring a section outside of the Allocation it starts in, thereby hiding other allocations.
Expected result: The Native Object should not be drawn outside of the Allocation it starts in, thereby hiding other allocations

Note: The Memory Profiler knows the Start Address of a Native Object and the size of it. It is not guaranteed that all memory associated with this Native Object and contributing to its size is continuous memory. I.e. different parts of the Native Object can be located in different Native Allocations. The Memory Map needs to take this into account when drawing these Native Objects.

7. b) Compare the Native Object's colors to those in the Legend at the top

Actual result: Legend and Chart color for this Native Objects do not fully match up. It is darker or lighter based on the Editor background theme.
Expected result: Legend and Chart color for Native Objects match up and are easy to read and contrast well.

Note: The Native Object is part of a Native Allocation that is not part of a Native Region (aka in the Memory Map as Native Memory (Reserved)). Therefore, both the Allocation as well as the Object are getting drawn at 40% opacity, blending with the editor background color.

Please note that 7. b) will likely have to be fixed as part of Case 1278203, see: https://issuetracker.unity3d.com/product/unity/issues/guid/1278203/

Reproducible with: Any Unity version from 2018.3 up and any version of com.unity.memoryprofiler that includes the Memory Map, up to and including 0.2.5-preview.1