Analyze Particles in Image Stack



I am a new user of ImageJ/Fiji and am having difficulties that I am unable to resolve. I created a stack of five images and applied thresholds of 64 and 246 to Brightness using Threshold Color (HSB). The threshold appears to be correctly applied to each image in the stack. The difficulty is when I then analyze the stack using Analyze Particles. Rather than getting the results for each image (slice), I get the results for the last slice repeated five times. If I split the stack into individual images and analyze them separately the results are fine What am I doing wrong with the analysis of the image stack?