Personally, I find the object selector dialogs a bit quirky.
The “guess as you type” feature in the Select Place Object Selector stopped being usable when my Place hierarchy grew complex.
The common suggestion is to “clipboard” Places that you expect to reference repeatedly in a data-entry session. This allows you to drag’n’drop a Place onto the Event Editor and avoid the object selector dialog entirely.
The other popular suggestion is to install @kku experimental addon called “recent-items”. This adds a shortlist of the most recently used objects at the top of each category’s object selector.