It shouldn't and doesn't, at least on my machine. All the options are remembered for next time but if you clear this option then the next time it opens up it remains cleared. Sounds like maybe your user settings are messed up somehow.
Unfortunately the settings for SSMS are all over the place. Some are stored in your Roaming directory while others are in Local. Yet more are in the registry. For the very specific setting you're looking for it is in the registry under HKCU\Software\Microsoft\SQL Server Management Studio\<version>\Find
. In the case of the current version of SSMS it appears to have a version of 18.0_IsoShell
. Within here is a series of three values AdornmentOptions
, DialogOptions
and Options
. There are 2 different find UIs in SSMS and these control those. In all 3 cases you can see the value of WholeWord=1
. Change that to WholeWord=0
and you should be good. Be sure that SSMS isn't running before you make those changes.