Possible problem with efficient memory handling

**Describe the bug**
On a Windows 11 box (with an uptime of ~5 hours), I noticed CopyQ was using 167MB of RAM (according to Windows Task Manager). This surprised me as CopyQ was configured to only have a single tab (the clipboard) and there were only 25 small text items stored in that tab (no images). Tags, encryption, synchronize, and FakeVim were all disabled.

I then went into CopyQ's Preferences UI and went to its `Layout` tab. Out of curiosity, I checked the `Hide tabs` checkbox and then clicked the `OK` button. Task Manager reported CopyQ's memory use instantly dropped from 167MB of RAM to 25MB.

That huge decrease makes me wonder if CopyQ has an issue with memory handling or if it has a memory leak.

**Version, OS and Environment**
CopyQ Clipboard Manager 13.0.0
Qt: 6.8.3
KNotifications: 6.12.0
Compiler: MSVC
Arch: x86_64-little_endian-llp64
OS: Windows 11 Version 25H2
Installed via [Scoop](https://github.com/ScoopInstaller/Extras/blob/master/bucket/copyq.json)