The optional Properties plugin contains a collection of settings for tracks or rack chains which are not directly available in the interface of Ableton Live. In this way, Properties behaves differently than other plugins: only one Properties plugin can exist on a track or in a chain.
An example is the track’s blend mode. Blend mode is a setting that defines the way the outputs of tracks are mixed (more detail here). This setting affects the entire track on which the Properties plugin is added. When there are two Properties plugins on one track, only the first is being used. The other device will display a warning.
The Properties plugin has different settings available depending on the type of track/chain it is added on. Also, some settings are not applicable for chains, and are disabled when the Properties plugin is added onto a chain.
Since multiple chains can exist in a track, chains can have different settings than their parent track. Chains within a track can be blended with different settings than those used to blend their parent track with other tracks. Therefore, a Properties plugin’s scope does not leave the chain. You can put a Properties plugin on each chain in an Audio Effect Rack and also put a Properties plugin on their parent track without conflicts.
On audio tracks (not on rack chains), the Properties plugin can define the video delay. This delay is different than the delay setting in Live. You can use this value to correct any latency inflicted by projectors, scalers or other intermediate hardware.