Search filter resets occasionally

[hurricup]

To reproduce:
- open UI
- search for something
- do other stuff
- list becomes unfiltered

Noticed cases:
- group removal in the groups combo-box
- pick and put a blueprint

[boskid]

Do you have a save file where the issue can be observed? Just because it clears "sometimes" does not mean it is on a timer, there may be some other events in game that happen (technologies researching for example) and without additional details there is not much that can be done. Also there is no game version so i cannot rule out if this was already covered by some other fixes.