From Ubuntu bug report:

Create a new text document. Press ctrl-S to save (or click the "floppy" button).
In the file dialog enter a file name "test". Press ctrl-A to select the whole
file name, then ctrl-C to copy it. Press Enter to save (or click on the save
button).

Result:
The file dialog hangs for several seconds, then closes. Back in the document,
typing is slow, the applications seems to hang for seconds at a time. Pressing
ctrl-V to paste the file name into the document takes seconds.

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This has been verified on official OOo with the gnome dialog.