LMMS clumsily interacts with VST

1) I tried to work with ReaPlugs - https://www.reaper.fm/reaplugs/ in LMMS. LMMS loads em but plugs Interface has no response... I can load presets in LMMS Vestige window but I cant manage plugs by internal elements. They work in another DAW.
2) When I change focus from (any) VST window to another I cant back it by clicking on internal interface of it. I must to click on border or title of VST window to back focus.
3) After reloading a project and pressing button Controls in FX Chains of mixer on VST FX then LMMS shows empty window or VST window with rectangle in right top. Need to press button Show/hide a few times to show it ok.
Will it get fixed or its' a system problem?

Reproduce the reported ReaPlugs behavior in LMMS: unresponsive plugin controls, focus loss between VST windows, and the malformed window after reloading a project. Start with Vestige and the mixer FX Chains Controls/Show-hide flow; done means these interactions work reliably without requiring border clicks or repeated toggling.

Written by the indexing model from the issue text.