Shift+Enter on a line ending with "+" should not fail before the following line is executed

[Kabouik]

Multiline code composed of lines separated with + runs correctly only when all lines are manually selected and then executed all at once with Ctrl+Enter or Shift+Enter. This makes it difficult to use the ggplot2 syntax for instance, as it is often made of several lines separated with + for ease of reading and editing, and there are probably other situations in R where separating lines with + is useful.

The expected behavior would be that sending a line ending with + waits for the next line to be sent too before throwing either an an output or an error, as the command should actually be ran in R only when the full command has been sent.