fix #146397. Clear container for html and plain text renderer.
fix #146397. Clear container for html and plain text renderer.

eamodio/vscode,microsoft/vscode,microsoft/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode,eamodio/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode,microsoft/vscode,microsoft/vscode,microsoft/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode