Can't change the backcolor of Textbox

[Axel123inkt]

I set the textbox backcolor to green and it stays gray when i run my application, the derivedstyle is false.

this is how i set my textbox:

this.TxtAantalMedewerkers.AutoCompleteCustomSource = null;
this.TxtAantalMedewerkers.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.None;
this.TxtAantalMedewerkers.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.None;
this.TxtAantalMedewerkers.BorderColor = System.Drawing.SystemColors.ControlDark;
this.TxtAantalMedewerkers.DisabledBackColor = System.Drawing.Color.White;
this.TxtAantalMedewerkers.DisabledBorderColor = System.Drawing.Color.White;
this.TxtAantalMedewerkers.DisabledForeColor = System.Drawing.Color.White;
this.TxtAantalMedewerkers.Font = new System.Drawing.Font("Century Gothic", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.TxtAantalMedewerkers.HoverColor = System.Drawing.Color.Transparent;
this.TxtAantalMedewerkers.Image = null;
this.TxtAantalMedewerkers.IsDerivedStyle = false;
this.TxtAantalMedewerkers.Lines = null;
this.TxtAantalMedewerkers.Location = new System.Drawing.Point(169, 188);
this.TxtAantalMedewerkers.MaxLength = 32767;
this.TxtAantalMedewerkers.Multiline = false;
this.TxtAantalMedewerkers.Name = "TxtAantalMedewerkers";
this.TxtAantalMedewerkers.ReadOnly = false;
this.TxtAantalMedewerkers.Size = new System.Drawing.Size(208, 25);
this.TxtAantalMedewerkers.Style = MetroSet_UI.Enums.Style.Light;
this.TxtAantalMedewerkers.StyleManager = null;
this.TxtAantalMedewerkers.TabIndex = 5;
this.TxtAantalMedewerkers.TextAlign = System.Windows.Forms.HorizontalAlignment.Left;
this.TxtAantalMedewerkers.ThemeAuthor = "Narwin";
this.TxtAantalMedewerkers.ThemeName = "MetroLite";
this.TxtAantalMedewerkers.UseSystemPasswordChar = false;
this.TxtAantalMedewerkers.WatermarkText = "";