[Rd] use of the tcltk package crashes R 4.0.1 for Windows

[Fox, John]

Hi,

The following code, from the examples in ?TkWidgets , immediately crashes R 4.0.1 for Windows:

--------------------- snip --------------------
library("tcltk")
tt <- tktoplevel()
label.widget <- tklabel(tt, text = "Hello, World!")
button.widget <- tkbutton(tt, text = "Push", 
	 command = function()cat("OW!\n"))
tkpack(label.widget, button.widget) # geometry manager
--------------------- snip --------------------

Session info (prior to the crash):

--------------------- snip --------------------
> sessionInfo()
R version 4.0.1 (2020-06-06)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 18363)

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] tcltk     stats     graphics  grDevices utils     datasets  methods  
[8] base     

loaded via a namespace (and not attached):
[1] compiler_4.0.1 tools_4.0.1   
--------------------- snip --------------------

I observe this behaviour both in the Rgui and when I run R in a terminal. I think the problem is general to the use of the tcltk package.

Best,
 John

-----------------------------------------------------------------
John Fox
Professor Emeritus
McMaster University
Hamilton, Ontario, Canada
Web: https://socialsciences.mcmaster.ca/jfox/