There have been some tweaks to Find Database Object over time, but you don't really have a problem in 19.1 (I assume that is what you are commenting on). Just click in the All Schemas checkbox. All schemas will be selected. Then click again to deselect all schemas except the current schema.
Even though All Schemas appears to greyed out (which can happen for both shared and unshared worksheet cases, actually), it is active.
I'm going to call that a bug, the unshared worksheet connection shouldn't be used to open an object search panel