Remove unnecessary (?) calls to Update

[pyscripter]

Remove Update call from TCustomSynEdit.UpdateScrollBars, TSynEditScrollBars.WMVScroll and DoMouseWheel.

Discussed in #176

^{Originally posted by MShark67 February 17, 2022}
When I converted the Scrollbar code, I kept the existing Update calls as I didn't want to change any behavior (perhaps ones I didn't understand.) Does anyone know why these are there? They cause issues if you need to load a number of SynEdits in a loop (basically each one will force paint itself, causing slowdowns and flashing.) Removing the calls fixes that issue and I haven't noticed any problems with removing them, but they must be there for a reason I don't know about.

[MShark67]

I just wanted to clarify that the other update call to possibly remove is the one in TCustomSynEdit.UpdateScrollBars. I've tested with removing this one and the ones in TSynEditScrollBars and so far, I haven't found a case where they're needed. And I totally agree that WM_SETREDRAW (or the new LockDrawing and UnLockDrawing built into TWinControl) works around the issues nicely. However, those extra calls just kind of bother me since I suspect they aren't needed.

[pyscripter]

Test for a little while longer and then please submit a PR to close the issue. Remove all calls to Update that are not needed.
Possibly the issue I had was related the WS_EX_COMPOSITED option that was removed. Not sure. Would be nice to get rid of those calls if they are not needed.