All dashboards can be changed to dark mode. If you update to of 6.5.4 or later that includes web dashboards.
Client dashboards can be changed either during creation (Use for Monitoring) or in the dashboard properties of existing dashboards.
We are trying to do our best to make our interfaces (rich client and web) work best on your desktop, or when you show a dashboard on lower-contrast devices such as projectors etc. Both interfaces support dark modes for dashboards for monitoring. Analytics workflows will be kept uniformly the same - which is white.
indeed, however not the rich clients builtin "dashboards" like host overview and application overview. Which is what our incident and problem center has been using so far :).
Its been displayed on a 50" flatscreen monitor for the last 4 years now, and i have to admit that it is indeed much "brighter". I guess we could adjust the contrast on it, but that would meddle with the other stuff they have going on on that NOC screen.
so yeah.. unfortunate design alteration with regards to how we use it. Its not functionality breaking, but i did get spammed this morning (people seeing the 6.5 version for the first time), regarding if i could make colouration/saturation the same as pre 6.5