OS: Windows 10
Java: OpenJDK v1.8u232 x64
ImageJ: v1.52r

When adding a calibration bar via Analyse->Tools->Calibration Bar, all changed dropdown choices, numbers and checkboxes will be remembered, but not the Bold text setting, i.e. when the dialog is opened again, every setting is left at its last value (how it should be) but one has to check Bold Text again if so desired.

Update: Added a pull request that should fix the issue: #89