How to make bubbles persist in bubble plot

[#1]

Hi 

I have a data table with x, y, ID, and time columns. There is a temporal phenomenon that I want to show with the data, so I am using a bubble plot with X = x, Y = y, ID = ID, Time = time. Each point appears at the appropriate x,y coordinate at the appropriate time. I used the ID field so that each point appears on its own and is not tied to other points over time. Unfortunately, each point disappears as soon as the next point appears. If I turn on trail bubbles, it gives me a transparent trail bubble for only one time increment then the trail bubble disappears. I would like each point to appear and persist for the duration of the animation. Does anyone know whether there's a setting that keeps the old points on the plot as new points appear?

Much obliged,

Greg

[#2]

Do all of your points have same amount of time values? Maybe they disappear because they don't have time anymore to show which some others do? So you might have to repeat the values until the last time values is reached

[#3]

Each data point appears at a new time step, for steps 1 through 1000.  I don't want to repeat each 'early' data point artificially just so they appear in subsequent time steps. In other words, to do as you suggest, data point 1 would need to be repeated 999 times; data point 2 would need to be repeated 998 times, etc. That would blow up the length of my data table substantially.