just barely … 
If the navigator is slow in dark mode only then could it be that the IDE is making repeated calls to IsDarkMode? Ive found that is a real PITA for performance.
I did a find/replace “.Mode” -> “.RunMode” and the IDE didn’t refresh the code.
First, I thought it didn’t find and replace then I searched again and it didn’t find anything (effectivly as it did it), but I had “.mode” in front of my eyes.
I closed and reopened my project and everything was ok.
You do know that you’re not meant to use it this way? May I ask why you were/are doing this?
[quote=457905:@Thomas ROBISSON]I did a find/replace “.Mode” -> “.RunMode” and the IDE didn’t refresh the code.
First, I thought it didn’t find and replace then I searched again and it didn’t find anything (effectivly as it did it), but I had “.mode” in front of my eyes.
I closed and reopened my project and everything was ok.[/quote]
Hi Thomas,
Are you using the Xojo 2019r2 Windows IDE when this happens?
I noticed this same behavior when searching-and-replacing deprecated items for the new ones. It’s difficult to reproduce (because I’d like to make a Feedback case for it), but seems to only happen after renaming several different things in a row. When it does happen, a simple restart seems to fix it.
I have not noticed this issue with the macOS IDE.
I was making a bad design choice. I refactored things to cache the value. I think based on comments you had made about retrieving the correct colours via declares in the Paint event rather than in the AppearanceChanged event.
Just switched to light mode… After taking 2 minutes to get my eyes adjusted to staring directly into the sun I can confirm that 2019r2 is “usable”. When switching back to dark mode, 2019r2 feels like trying to run through a swimming pool.
2019r2 in light mode = 2019r1.1 in dark mode.
Navigator is probably the slowest component in 2019r. The code editor is alright but switching between methods is just slow to be productive.
Side note, I am running at 2.0x scaling.
Scott, I use Cojo 2019r2 under Mac OS Mojave. And yes, i did 2 or 3 Find/Replace before I see this trouble.
I have still many many many* :-/ find/replace to do then I suppose I will reproduce the problem.
note * :
MyString = “many”
For iNbr = 1 to 1000000
MyString = MyString + " many"
next iNbr
Msgbox, sorry, MessageBox MyString
I made an app that ran 10million iterations of IsDarkMode in both 2019r1.1 and 2019r2 with dark mode on and off, no difference.
25% tariff on IDE speed.
I know that. The Xojo IDE is written in Xojo. I was just wondering if internally it is calling IsDark mode excessively.
I have the same problem. MacOS Mojave, MBP Retina with SSD and 16GB memory, Xojo 2019r2 with dark mode is very sluggish. The code editor performance is workable, but scrolling in the navigator is dramatic. As soon as I switch to Light mode performance seems equal to 2019r1.1.
Other thing with 2019r2: opening GraffitiSuite Demo Web project (that already took quite long to load in 2019r1.1) now crashes Xojo somewhere halfway of loading… (showing ccTooltip in the loading dialog) every time… Anyone else experiencing this?
[quote=460166:@Robert Everts]Other thing with 2019r2: opening GraffitiSuite Demo Web project (that already took quite long to load in 2019r1.1) now crashes Xojo somewhere halfway of loading… (showing ccTooltip in the loading dialog) every time… Anyone else experiencing this?
[/quote]
Yes, I too am seeing this I assumed it was just me!
@David Cox and @Robert Everts
This has been reported to Xojo and reproduced. Hopefully it’s fixed soon. In the meantime, opening GraffitiSuite in 2019R1.1 is the best bet.
Ive submitted a full (1.6 GB) Trace Log to the FR days (weeks?) ago and they did not even took a look into it. 
@David Cox , @Robert Everts , @Sascha S
I have just released GraffitiSuite R30.2 which corrects the crash issue in 2019R2.
Im not sure how you know that we havent looked into it. Keep in mind that a 1.6GB log file might as well be 1.6 Terabytes when it comes to evaluating a bug. Talk about finding a needle in a haystack.