Numbers, Bullets and Indent paragraph will clear the Block Styles setting

[satya]

To Reproduce the defect

1. open ajax sample

2. input some text, select the text and apply a Style(eg: Red Title)

3. select these contents and click on "Numbers/Bullets/Indent Paragaph" icons

Expected Result:

Contents should be marked both Red Title and Numbers

Actual Result:

Block Styles is cleared by the Numbers/Bullets/Indent setting, like below

[garry.yao]

Duplicate of #3257.