Hi @dannymx Thank you very much for the post, and thank you for following up with a workaround. We’re aware of these types of issues but are difficult to reproduce, appreciate you flagging this one.
For the past few days, my file tree has also been lagging a lot on my MacOS M2 Pro. When I disable the following extension the lag is 90% resolved: Open VSX Registry
I think I found the trigger for the theme-dependent lag reported here: the selection.background theme key.
I had the same symptoms (laggy Explorer scrolling, window renderer process CPU spiking) on Solarized Light. I rebuilt that theme piece by piece on top of Light+ via workbench.colorCustomizations and bisected it to one key. Minimal repro on any theme:
Scroll the Explorer → lag + renderer CPU spike. Remove the key → instantly smooth.
The value doesn’t matter: translucent (#878b9180), opaque (#C2C1BA), the default selection blue (#ADD6FF), even fully transparent (#C2C1BA00) all reproduce it. Only removing the key fixes it, so the trigger seems to be the presence of a custom ::selection rule, not the color. Themes that define this key (Solarized Light does) would lag; themes that don’t would be fine — which may explain why only some themes are affected in this thread.
Ruled out: reproduces with --disable-extensions, with --disable-gpu, on local folders (not SSH), after full restart, on a small workspace.
