I’ve released a new ImageJ plugin that allows to draw user attention on the status bar or on specific image windows by permanently or temporarily giving those objects a chosen color.

It’s located in Plugins>Utilities>Alert.
Choose object to apply alert to from status bar or active image.
Choose color to apply
Use a duration>0 for just flashing the color. 500 will change the color for 500 ms.
Or use duration<=0 to change the color permanently.
In a macro, use something like:
run("Blobs (25K)");
run("Alert ", "object=Image color=Green duration=1000");
You can get this plugin by activating the IBMP-CNRS Fiji update site, or in ImageJ by getting the jat file from GitHub - mutterer/alert
Jerome.