Displaying help in R immediately (Rstudio) - r

Question

I am creating a package in R that will have a GUI interface through the tcltk package. A front end function will get the data from the user through a GUI and call a back end function which returns the results back to the front end. I currently have written all of the documentation for the functions, and except for this part and a bit of bug testing the functions are also complete.
To help the user out, I want to be able to print the documentation. In Rstudio this displays it in the help window (it is important to note that this window is not created by my code through the tcltk package, this window is a part of Rstudio).
If my function only interacts with the user through the command line, I can get the help screen in Rstudio to update immediately. However, if I am using the graphics, the help window won't update until after the function is done, which defeats the purpose of having it print the help screen in the first place.
Below is an example of a GUI window created through the tcltk package. I'm using var.test as an example documentation here, so make sure your help window is on something else to see when the help screen updates.
require(tcltk)
print(help(var.test))
hi <- tktoplevel() #creates a window
ok <- function() # this function is called by pushing the button defined below
{
print("Goodbye, World!")
tkdestroy(hi) # destroys the window
}
print("Hello, World!")
ok.button <- ttkbutton(hi, text = "This is a button", command = ok) #defines the button
tkgrid(ok.button) #puts the button on the window "hi"
tkfocus(hi)
tkwait.window(hi)
As you can see, even calling the help function first, before the tcltk graphics window is even created, doesn't make the help window update. The print function still seems to work, as "Hello, World" is printed before one presses the button.
For my functions to work properly, I must use the tkwait.window(), otherwise the front end won't sync with the back end.
If getting the Rstudio window to update isn't really possible, then an alternative solution that uses a different window or program would be acceptable.

Answer 1

Add a small delay into your code after trying to print the help:
....
print(help(var.test))
# Sys.sleep(0.01) # too short
Sys.sleep(0.5) # long enough
...
This works in Linux and Windows...
I guess RStudio is not updating the GUI while executing the R command batch (all commands that you send to R at once) because it blocks updates executes R in a "blocking sub thread" and therefore behaving like "single threading" so that the GUI cannot be updated until the execution of the R batch ends.
The sleep function seems to return the control to the RStudio (GUI?) process so that it can update the GUI.
If you reduce the sleeping time too much you can observe partial updates of the RStudio GUI.
PS: Using process.events() does not work!