Bob,
I tried some simple tests involving backslashes with the MyEclipse Property editor – while it wrote the files to disk fine, on reopening the file, it displayed values that were different from the on-disk version, with the backslashes removed. I’ll ask the team to take a look at this.
In the meanwhile, you could use a simpler editor named, Properties File Editor
by choosing this editor from the Open With context menu entry for the file – if required you could make this a permanent editor choice as well, from the General > Editors > File Associations preference page. Do you often use the tabular view of the properties that the MyEclipse Property Editor provides?
Apologies for the inconvenience caused.