Bug 399151

SUMMARY
Hi, I love Kate and use it every day; thank you. One feature I've used for years it the Quick Open Search (mapped to Ctrl+Tab) which lets me quickly change files. The number of open files in my main project has not changed in magnitude, yet recent updates to Kate seemed to behave magnitudes slower, taking up to 3-4 seconds to even open the Quick Open Search. I'm running 18.04.3 which is the latest version available in Fedora 28. Before I dive into performance analysis with pstack, perf, etc., I wanted to check if there are known issues in this area of code that may have caused a regression or if this is a consequence of a by-design change that is required?

STEPS TO REPRODUCE
1. Open a few thousands files in Kate
2. Open Quick Open Search
3. Observe it takes multiple seconds just to open the dialog, but on older versions this was much faster

OBSERVED RESULT
Slow performance

EXPECTED RESULT
Better performance as in previous releases

SOFTWARE VERSIONS
(available in About System)
KDE Plasma Version: 5.13.4
KDE Frameworks Version: 5.48.0
Qt Version: 5.11.1

ADDITIONAL INFORMATION
Might be related to bug 387360, although I'm not opening a different number of files than what I had in older versions when it was faster.