UI fixes

[ian-tjahjono]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 257

• 6 of 16 (37.5%) changed or added relevant lines in 5 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+1.4%) to 64.12%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/main/java/seedu/address/logic/parser/AddressBookParser.java	0	1	0.0%
src/main/java/seedu/address/ui/MainWindow.java	2	3	66.67%
src/main/java/seedu/address/model/ModelManager.java	2	10	20.0%

Files with Coverage Reduction	New Missed Lines	%
src/main/java/seedu/address/model/ModelManager.java	2	41.7%

Totals
Change from base Build 249:	1.4%
Covered Lines:	2593
Relevant Lines:	4044

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💛 - Coveralls