Fix an event handler to fire only the one time it is needed (BL-8619)
Fix an event handler to fire only the one time it is needed (BL-8619)

I found this in the course of fixing BL-8619.  I don't know if it helps
that issue directly, but it seems an obvious fix that is needed.

gmartin7/myBloomFork,StephenMcConnel/BloomDesktop,gmartin7/myBloomFork,gmartin7/myBloomFork,gmartin7/myBloomFork,BloomBooks/BloomDesktop,gmartin7/myBloomFork,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,BloomBooks/BloomDesktop,BloomBooks/BloomDesktop,StephenMcConnel/BloomDesktop,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,StephenMcConnel/BloomDesktop,StephenMcConnel/BloomDesktop,gmartin7/myBloomFork,BloomBooks/BloomDesktop