Missing placeholder text in compose area when deleting multiple lines

[threema-danilo]

Bug Description

Sometimes the compose doesn't show a placeholder text even though it's empty.

Steps to Reproduce (for bugs)

Firefox:

1. Type "a<shift+enter>b"
2. Press ctrl+a to select all text
3. Press ctrl+x to cut text

Chromium:

1. Type "a<shift+enter>b"
2. Press ctrl+a to select all text
3. Press ctrl+x to cut text
4. Paste text, and repeat steps 2 and 3

In both situations, the contenteditable div now contains a single <br> which prevents the placeholder from showing up.

Your Environment

• Threema Web version: 2.5.3
• Browser name and version: Firefox 124.0.1 / Chromium 123
• Computer operating system and version: Arch Linux

[threema-danilo]

Seems like this fix stopped working:

threema-web/src/directives/compose_area.ts

Lines 347 to 352 in 82c83c6

	// If the compose area contains only a single <br>, make it fully empty.
	// See also: https://stackoverflow.com/q/14638887/284318
	const text = composeArea.get_text(true);
	if (text === '\n') {
	composeDiv[0].innerText = '';
	}