Extra space characters added to a table are removed when using Chrome or Safari, not Firefox

Summary

**NOTE: As the space characters are removed here in the current display of JIRA, view the notes below in "Text" mode to see the formatting and spaces in the example text snippets below.  Or, see the attached video.**

When adding text containing strings of multiple space characters into a table on a Confluence page, the extra space characters are truncated to a single space ' ' character after saving and viewing the page.

Example text:
---------
Line 1 without spaces.

Line 2 with spaces at the beginning and in the middle of the text.

Line 3 without spaces.
---------

Becomes:
---------
Line 1 without spaces.

Line 2 with spaces at the beginning and in the middle of the text.

Line 3 without spaces.
---------

This behavior is only reproducable specifically when typed into a table and using Chrome and Safari. Firefox maintains the space characters. Copying and pasting the text into the table also maintains the spaces. When adding the text in normal area on a page, retains the additional space characters as intended.

When testing this on Firefox, the additional space characters are retaines in the table as well as normal areas.

Environment

• Reproduced with Confluence (version 6.3.2 and 6.5.0)
• Reproduced with Chrome (Version 62.0.3202.94 (Official Build) (64-bit))

It likely affects other versions of Confluence as well.

Steps to Reproduce

1. Create a new Page.
2. Type in text containing extra space characters, such as the following:
---------
Line 1 without spaces.

Line 2 with spaces at the beginning and in the middle of the text.

Line 3 without spaces.
---------
3. Create a table of any size (2x2) for example.
4. Type or paste the same text.
5. Verify that the text in the normal page area retains the extra spaces, but the text in the table removes the extra spaces and becomes:
---------
Line 1 without spaces.

Line 2 with spaces at the beginning and in the middle of the text.

Line 3 without spaces.
---------

Expected Results

The extra space characters should be retained.

Actual Results

The extra space characters are only removed for text typed in Chrome in the table.

Notes

We can see in the Storage Format that the extra space characters that are maintained are stored as   characters.

Workaround

• Use Firefox.
• Copy and paste the text with the space characters from another area on the page or another source