Cannot copy text data from Win10 guest onto Mac OS host

[TonyRockyTiger]

Host: MacOS High Sierra (10.13.5)
Guest: Windows 10 64-bit; Guest Additions installed; bi-di copy&paste enabled
VirtualBox Version: 5.2.18 r124319 (Qt5.6.3) - latest as of Aug 28, 2018; latest Extenions installed

Issue:

Copying any rich-text data from within the Windows 10 guest is not paste-able into the Mac OS host. This is somewhat new behavior that was introduced with a clipboard crash fix in the release after version 5.1.32.

Before the crash fix was made, pasting copied rich-text from the guest onto the host pasted the plain text extracted from the clipboard. While not as "perfect" of a feature solution as being able to paste the full rich-text, plain text pasting would be welcomed back with open arms. An ongoing discussion is here:

​https://forums.virtualbox.org/viewtopic.php?f=8&t=86056&sid=ef11b0345dfa4278164ef407b4f4a626

While most of the commenters experiencing this bug are seeing the issue with Microsoft Office products, I also see it with Chrome and Firefox. To reproduce, do the following:

1) within Win10 guest, browse to Google from within Chrome or Firefox, do a search for "virtualbox" 2) highlight and copy the first found result, which is "Oracle VM Virtualbox". I copied the entire result listing: title, URL, description. 3) hit CTRL+C or right-click/copy 4) mouse-out to Mac OS host and paste into any app such as TextEdit: no data is pasted.

The very inconvenient workaround that most people do is to paste the data into Notepad within the Win10 guest, copy that data, then paste into the host. A nicer solution that still requires an extra click is to install the PureText app within Win10, which when used, strips the rich text and makes the plain text paste-able into the Mac OS host.

We would like to have the ability to paste any text data (as at the minimum plain text) into the host, which was working in VirtualBox up until and including 5.1.32.

[TonyRockyTiger]

The first paragaph had its newlines stripped by the bugtracking software, making the context info harder to read.

[Socratis]

Duplicate of #15960, as a result of changes in #15782, due to a crash as described in #16242.